| o'clock | = | hora |
| oak | = | quercus |
| oak tree | = | quercus |
| oaken | = | quernus |
| oar | = | remigium |
| oath | = | juramentum, promitto, sacramentum |
| oath-breaking | = | periurium |
| oats | = | avena |
| obedience | = | famulatus, obsequium |
| obedient to , be - (vb) | = | pareo (+ dat.) |
| obediently | = | obedienter |
| obeisance | = | famulatus |
| obey (vb) | = | obtempero |
| obey | = | famulor, pareo (+ dat.) |
| object | = | res |
| object causing fear | = | timor |
| objection | = | contradictio |
| obligation | = | gratia, officium |
| oblige | = | commodo, adstringo (persons) |
| obliging | = | beneficus, comis, comis, prolixus |
| obliter | = | aboleo |
| obliterate (vb) | = | annullo, deleo |
| obliterate | = | eradico |
| oblivion | = | oblivio |
| oblong shield | = | scutum |
| obscure | = | ignotus |
| obscurity | = | silentium |
| observation | = | speculatio |
| observe (vb) | = | contemplor, conspicio |
| observe | = | custodio, video vidi visum, intueor, servo |
| obstacle | = | impedimentum, obstaculum |
| obstinacy | = | pertinacia |
| obstinate | = | tenax, pertinax |
| obstinately | = | pertinaciter |
| obstruct | = | retardo, impedo, impedio |
| obtain (by asking) | = | impetro |
| obtain (vb) | = | usurpo, adepto |
| obtain | = | adipiscor, acquiro, conciliare, mereo, quaero |
| obtain | = | potior |
| obtain by service (vb) | = | emerio |
| obtain one's desire | = | insumo |
| obtaining | = | adeptio |
| obtuse | = | stolidus |
| occasion | = | indo (past indidi), vicis, excito, casus, illata |
| occasionally | = | aliquando |
| occupation | = | negotium |
| occupy (vb) | = | occupo, teneo |
| occupy | = | preoccupo |
| occupy oneself (vb) | = | fungor, fungi, functus |
| occur (vb) | = | occuro, occurro |
| occur | = | evello (-ere, velli, vulsum), accido, incido |
| occurrence | = | res, eventus |
| Oceanus | = | Oceanus |
| odiferous, be - | = | fragro |
| odor | = | odor, nidor |
| odour | = | odor |
| of | = | ab |
| of a father | = | paternus, paterna |
| of a former time | = | veter |
| of a great value | = | pluris (gen.) |
| of a king | = | regalis |
| of a master | = | vaco |
| of a soldier | = | militaris -e |
| of age | = | adultus (adj.) |
| of all kinds | = | omnigenus |
| of any kind whatever | = | qualiscumque |
| of benefit | = | prosum (profuturus) |
| of cloth | = | picturatus |
| of course | = | quippe, nimirum, scilicet |
| of crystal | = | crystallinus |
| of great promise | = | bonae indolis |
| of immoderate size | = | ingens |
| of iron | = | ferrarius |
| of long duration | = | diuturnus |
| of long-standing | = | inveteratus |
| of many kinds | = | multigenus |
| of milk | = | lacteus |
| of no effect | = | irritus |
| of noble birth | = | generosus |
| of not effect | = | irritus |
| of one mind | = | unanimis |
| of one time or another | = | quandoque |
| of one's own accord | = | sponte, ultroneus |
| of or from Flanders | = | flandrensis |
| of property | = | vaco |
| of rain | = | pluvialis, imbrium |
| of saffron | = | croceus |
| of service, be - | = | facio |
| of some size | = | aliquantus (adj.) |
| of such a kind | = | talis |
| of such a size | = | tantus |
| of the highest worth | = | plurimi |
| of the morrow | = | crastinus |
| of the opinion of , be - (vb) | = | opinor |
| of the people | = | publicus |
| of the stomach | = | cardiacus |
| of today | = | hodiernus |
| of tomorrow | = | crastinus |
| of use | = | accommodatus, accommodus |
| of use, be - | = | proficio |
| of what kind | = | cuiusmodi |
| of what kind? of the kind that | = | qualis |
| of what sort you will | = | qualislibet |
| OF WHICH there were not a few | = | quorum (neut. pl. gen.) |
| OF WHICH we know | = | quarum (fem. pl. gen.) |
| offence | = | commissum |
| offend | = | laedo ledo, offendo |
| offense | = | noxa, offensus |
| offensive | = | obscoena |
| offer (vb) | = | praebeo, obicio obieci obiectum |
| offer | = | praesto, praesto presto, polliceor, exhibeo exibeo |
| offer a price (vb) | = | liceor |
| offer for sale | = | vendo |
| offer to buy (vb) | = | liceor |
| offering | = | holocaustum, vitualamen, pollicitas, charitas |
| office | = | officium |
| office of ambassador | = | legatio |
| office of legate | = | legatio |
| official | = | persona |
| official dignity or office | = | honor |
| offshoot | = | suboles, germen |
| offspring | = | incrementum, suboles, suboles, liber, posteritas |
| often | = | pluries, quotiens, crebro, sæpe, saepius sepius |
| often simply | = | hereditas |
| oh | = | ah |
| oh woe unutterable! | = | infandum |
| oily | = | pinguis, lubricus |
| ointment | = | unguentum |
| OK | = | bene |
| okay | = | bene, bonus |
| old , be - (vb) | = | seneo |
| old , become - (vb) | = | consenesco, senesco |
| old | = | provectus, anus, grandaevus, vetustus, vetus |
| old age | = | canities, senium, senectus |
| old days | = | priscus |
| omen (bad) | = | parro |
| omen | = | monstrum |
| omit (vb) | = | omitto |
| omnipotent | = | omnipotens |
| on a grander scale | = | inflatius |
| on account of | = | præ, prae se ferre, pre se ferre, propter (+ acc.) |
| on all sides | = | undique |
| on behalf of | = | pro (+ abl.) |
| on both sides | = | utrimque |
| on condition that | = | per sic quod |
| on every side | = | hinc hinc |
| on good authority | = | comperte |
| on high | = | sublime |
| on no occasion | = | nusquam |
| on one's guard | = | praecautus |
| on purpose | = | consilio |
| on that account | = | ideo, idcirco |
| on the contrary | = | immo, ymo (immo), immo |
| on the far side of | = | ultra (+ acc.) |
| on the lower side | = | inferne |
| on the morrow | = | cras (adv.) |
| on the one hand | = | sive |
| on the other hand | = | rursus, nam, autem, vicissim |
| on the right | = | dexter |
| on the spot | = | ilico, statim |
| on the way | = | obviam, obviam (adverb), obvius |
| on which account | = | quamobrem |
| once | = | olim, quondam, olim, quondam |
| once and a half | = | sesquialter |
| once more | = | iterum |
| once only | = | semel |
| once, at | = | simul, continuo (adv.), statim |
| one .. the other | = | alter .. alter |
| one | = | unus, unus, una, unum |
| one after the other | = | invicem, crebro |
| one and a half | = | emiolios |
| one and a half times | = | sesqui |
| one and a third | = | sesquitertia |
| one apiece | = | singuli |
| one at a time | = | singulus |
| one by one | = | singulariter |
| one devoted to pleasure | = | voluptarius |
| one each | = | singuli, singulus |
| one enthroned on high | = | altithronus |
| one hundred | = | centum, centum |
| one of the best | = | optimus |
| one ought | = | oportet |
| one prematurely born | = | abortivus |
| one should | = | oportet |
| one thousand | = | mille |
| one time .. at another, at | = | modo..modo |
| one time | = | quondam |
| one time, at | = | quondam |
| one time..then, at | = | nunc quidem |
| one who carves food | = | carptor |
| one who fattens fowls | = | fartor |
| one who fight from a chariot | = | essedarius |
| one who gives evidence | = | testis |
| one who goes bond | = | cautor |
| one who is on his guard | = | cautor |
| one who kisses | = | basiator |
| one who lies in wait | = | insidiator |
| one who makes a pattern | = | digestor |
| one who pleads on behalf | = | deprecator |
| one who provides for | = | provisor |
| one who punishes | = | castigator |
| one's gaze fixed and frozen (vb) | = | definxu obtutu |
| one's native country | = | patria |
| one's own | = | proprius |
| one's own master , be - (vb) | = | esse suae potestatis |
| one's own master | = | sui juris |
| one-time | = | quondam |
| onion | = | cæpa, bulbus |
| only | = | solus |
| only | = | tantum, solus, solus, solum, solum (adv), modo |
| only begun | = | inchoatus |
| only just | = | tantummodo |
| only one | = | unus |
| onself noticed, make (vb) | = | suboleo (3 persons only) |
| onset | = | impetus, procella |
| open , be - (vb) | = | pateo |
| open | = | expositus, patefacio, directus |
| open sea | = | pelagus |
| open to all | = | publicus |
| opening | = | foris |
| openly | = | aperte, candide, libere, palam |
| openness | = | ingenuitas |
| opinion | = | sententia, sententia, iudicium, opinio, censura |
| opium | = | opium |
| opponent | = | antagonista, inimicus, adversarius, adversarius |
| opportune | = | opportunus |
| opportunely | = | opportune (adv) |
| opportunity | = | casus, vicis, commodum, occasio, oportunitas |
| oppose (vb) | = | obsto, adversor |
| oppose | = | occurro, resisto, oppono opposui oppositum, refuto |
| oppose verbally | = | contradico |
| opposed | = | contrarius, diversus |
| opposed to | = | contra |
| opposing. | = | adversus (adj.) |
| opposite | = | adversus (adj.) |
| opposite, be - | = | oppono opposui oppositum |
| opposition | = | adversitas, contradictio |
| oppress (vb) | = | gravo |
| oppress | = | excorio, conculco, onero |
| oppressed | = | gravatus |
| oppression | = | concussio |
| opress | = | plumbeus |
| opulence | = | luxuria, opulentia |
| opulent | = | locuples, dives |
| or | = | vel, an, aut |
| or against | = | provisor |
| or convey across | = | transporto, transmitto |
| or countryside | = | agrarius |
| or crowds | = | gregatim |
| or fit | = | adapto |
| or if | = | sive seu |
| or issue | = | proventus |
| or it begins | = | infit |
| or not | = | necne |
| or phrases in a manuscript | = | lacuna |
| or shod with iron | = | ferramenta |
| or some size | = | aliquanta (adj.) |
| or take away | = | abduco |
| or upon | = | incresco (-ere) |
| or wholly | = | contrado |
| oracle | = | oraculum |
| orate | = | oro, declamo |
| oration | = | oratio |
| orator | = | rhetor, orator |
| oratorical | = | oratorius |
| oratorically | = | oratorie |
| oratory | = | oratorius |
| orb | = | orbis |
| orbit | = | orbis |
| orchard | = | arbustum |
| ordain (vb) | = | monstro |
| ordain | = | monstro, scisco, volo |
| order (vb) | = | facio + inf., iubeo, iubeo iussi iussum |
| order | = | ordo, jussio, decretum, ordinatio, mando, mandatum |
| order of, by - | = | iussu (abl.) |
| ordering | = | discessio |
| orderly | = | castigatus, modestus, ordinatus, compositus |
| orders, give - (vb) | = | impero |
| ordinance | = | sanctio, scitus, edictum, decretum |
| ordinarily | = | ordinatim |
| ordinary | = | vulgaris, solitus, profanus, modicus, mediocris |
| ordinary manner | = | vulgariter |
| organization | = | norma |
| orgy | = | orgia, orgia |
| origin | = | satus, primordium, initium, ortus, profectio |
| original | = | exemplar |
| originate | = | emanio |
| originator | = | auctor |
| ornament | = | decus, ornatus |
| ornamented with | = | baccatus |
| ornaments | = | honor |
| ornately | = | ornate |
| orphan | = | pupillus pupilla, orbus, pupillus |
| ostentation | = | jactantia |
| other | = | alius |
| other | = | ceterus |
| other one | = | alter altera alterum |
| others | = | ceteri |
| otherwise | = | alioqui (adv.), alter (adv.), alioquin (adv.) |
| otherwise bring upon (vb) | = | infero |
| otherwise than | = | secus + atque or quam |
| our | = | noster nostra nostrum |
| OUR hearts beat as one | = | noster nostri |
| our ours | = | noster nostri, noster nostri |
| ours | = | noster nostra nostrum |
| out of , become - (vb) | = | subnascor |
| out of | = | e, ex |
| out of doors | = | foras, foris |
| out of one's mind | = | demens (dementis ) |
| out of ones senses | = | amens |
| out of place | = | incongruens |
| out, give - (vb) | = | tribuo |
| out-of-the-way roads | = | devia |
| outcome | = | eventus |
| outcry | = | vociferatio, clamor |
| outer | = | externus |
| outermost | = | extimus, extremus |
| outlander | = | barbaricus |
| outlandish | = | alienigena |
| outlaw | = | interdico |
| outlay | = | impensa |
| outlet | = | exitus |
| outrageous | = | improbus |
| outre-mer | = | transmaritanus |
| outside | = | foras, extraneus, extra, foris, externus |
| outside of | = | extra |
| outspread | = | diffusus |
| outstanding | = | palmarium |
| outstanding, be - | = | praesto |
| outstrip | = | supero |
| outward | = | extrarius |
| outwardly | = | extrinsecus |
| oven | = | clibanus |
| oven, small | = | fornacula |
| over | = | super (adv.), super |
| over there | = | illac |
| overall | = | totus |
| overbearing | = | superbus |
| overcloud (vb) | = | obnubilo |
| overcome (vb) | = | convinco, convinco, flecto |
| overcome | = | vinco vici victum, expugno |
| overflow (vb) | = | exundo, redundo |
| overflow | = | superfluo, redundo |
| overflowing | = | redundantia, abundans, proluvies, inundantia |
| overhang | = | incumbo |
| overhtrow | = | subruo subruti subrutum |
| overlook | = | despecto |
| overmatch | = | vinco |
| overmuch | = | nimis, nimis (adv.), nimium (adv.) |
| overpower | = | opprimo, opprimo oppressi oppressum |
| overseas | = | transmaritanus |
| overseer | = | vilicus, villicus, curator |
| overtake (vb) | = | supervenio |
| overtake | = | adipiscor, deprehendo |
| overthrow (vb) | = | subversio, prosterno |
| overthrow | = | perverto, subvertio, cædere, verto, everto |
| overturn (vb) | = | subverto |
| overturn | = | everto, perverto |
| overwhelm (vb) | = | obruo |
| overwhelm | = | premo, opprimo oppressi oppressum |
| ow | = | ah |
| owe (vb) | = | debeo |
| own up | = | confiteor confessus |
| owner | = | erus |
| ownership | = | proprietas |
| ox. bull | = | bos (bovis ) |
| oxen, team | = | iugum |
| oyster | = | ostrea |