Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
in-stĭmŭlo, āvi, ātum, 1, v. a., to prick or urge on, to stimulate (poet.): aliquem, Ov. F. 6, 508: verbis, id. M. 14, 495; Stat. Th. 1, 715: voce, Sil. 2, 543: falso instimulari, Dig. 5, 2, 3.