object, propose, protest, and decline
obliging, kind, helpful, and courteous
obscure, shadowy, intricate, and mysterious
obsequious, cringing, fawning, and servile [obsequious = fawning.]
observations, sentiments, ideas, and theories
obstinacy, pertinacity, stubbornness, and inflexibility [pertinacity = persistent]
offensive, disagreeable, distasteful, and obnoxious
officious, impertinent, insolent, and meddlesome
P
particular, precise, formal, and punctilious [punctilious = scrupulous]