Obstinant, "if he be obstinant" (IP[346],b), obstinate: the O.E.D. records the word as a substantive, earmarking it "rare," and giving a single quotation only, but the adjectival form is absent.
Occupy, "a merchant's place to occupy" (IP[339],b), formerly occupy was almost as hard-worked a verb as the modern American fix. Amongst other senses it meant, take possession, seize, enter upon, hold, have in possession, enjoy, reside in, tenant, stay, abide, employ, busy about, engage, make use of, etc.
Odible, "as carene is odible" (M[32],d)—"dispectuous and odible" (M[33],b), hateful, odious. "His face was so hatefull and so odyble."—Lydgate, Chron. Troy (1412-20), III. xxiv.
Old Boy, "play ever ... the old boy" (N[75],b), as one who has become skilled, clever, knowing through practice and experience; foreshadowing the slang usage: cf. "olde souldier, veteranus" (Huloet., 1552).
Om (passim), them—'em.
Ont (passim), on it—ont.
Opray, Opry, "opray counsel" (N[71],c)—"such opry" (N[71],c), not in O.E.D.:? = operary, practical.
Organs, "Piers Pickpurse playeth at organs" (R[240],a), i.e. as if fingering an organ: formerly organs (pl.) denoted a single instrument.
Osculare, "osculare fundamentum" (M[8],c), the modern vulgar jeer wrapped up in Latin.