Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
cŭpītor, ōris, m. [Sanscr kup, to be in active motion, to be angry; cf. recupero], one who desires or wishes (very rare; perh. only in the foll. exs.): incredibilium, Tac. A. 15, 42: matrimonii, id. ib. 12, 7: amicitiae, App. Flor. 3, p. 807.