| Word | Meaning | Occurrences |
|---|---|---|
| objurgo | to chide, scold | 3 |
| oblatio | offering, sacrifice | 118 |
| oblectamentum | pleasure, amusement | 1 |
| oblectatio | delight | 5 |
| oblecto | to delight, divert | 6 |
| obligatio | binding, entangling | 3 |
| obligo | to bind up, bandage | 6 |
| obliquus | slanting, oblique | 4 |
| oblivio | forgetting, forgetfulness | 30 |
| obliviosus | forgetful, oblivious | 2 |
| obliviscor | to forget | 125 |
| oblivium | forgetfulness, oblivion | 2 |
| obloquor | to speak against, interrupt | 1 |
| obmutesco | to become dumb, be silent | 14 |
| obnixe | with all one’s strength | 2 |
| obnoxius | liable to punishment, guilty | 7 |
| obolus | obol, small Greek coin | 5 |
| oborior | to arise, appear | 1 |
| oboth | Oboth | 3 |
| obrigesco | to stiffen | 2 |
| obrizus | refined, pure | 5 |
| obruo | to overwhelm, overthrow | 12 |
| obscuro | to darken, obscure | 24 |
| obscurus | dark, obscure | 10 |
| obsecratio | prayer, supplication | 29 |
| obsecro | to pray, implore | 135 |
| obsequium | compliance, obedience | 16 |
| obsequor | to comply, yield | 3 |
| observabilis | to be observed | 1 |
| observantia | observance | 1 |
| observatio | watching, observance | 11 |
| observo | to watch, observe | 94 |
| obses | hostage | 9 |
| obsideo | to besiege | 53 |
| obsidio | siege | 15 |
| obsigno | to seal, seal up | 2 |
| obsisto | to stand against, to oppose | 2 |
| obsordesco | to become dirty, be soiled | 1 |
| obstetrico | assist in childbirth | 3 |
| obstetrix | midwife | 6 |