Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
ĭneptĭo, īre, v. n. [ineptus], to talk or act absurdly, to trifle, play the fool (poet.): ineptis, Ter. Ad. 5, 8, 11; id. Phorm. 2, 3, 73: desinas ineptire, Cat. 8, 1.