| odious(adjective, nasty, terrible, disgusting, vicious) |
| offenseless(adjective, kindly, ignorant, naive, unknowing) |
| offensive(adjective, nasty, terrible, disgusting, vicious) |
| old-time |
| old-world |
| onerous(adjective, dull, boring, tired, tedious) |
| open(adjective, kindly, ignorant, naive, unknowing) |
| oppressive(adjective, dull, boring, tired, tedious) |
| ornery(adjective, mean, nasty, terrible, disgusting) |
| out of element(expression, adjective, idiom, inadequate, useless) |
| out of place(expression, adjective, idiom, inadequate, useless) |
| out of shape(expression, adjective, idiom, inadequate, useless) |
| outmoded |
| pesky(adjective, nasty, terrible, disgusting, vicious) |
| pestiferous(adjective, nasty, terrible, disgusting, vicious) |
| pestilent(adjective, evil, dislike, disgusting, beastly) |
| plaguesome(adjective, evil, dislike, disgusting, beastly) |
| plaguy(adjective, evil, dislike, disgusting, beastly) |
| poor(adjective, weak, inadequate, unfit, unqualified) |
| poorly(adjective, inadequate, useless, inappropriate, unhealthy) |