Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
sullātŭrĭo, īre, v. desid. n. [Sulla], to imitate or play the part of Sulla: ita sullaturit animus ejus et proscripturit, Cic. Att. 9, 10, 6; cf. Quint. 8, 3, 32; 8, 6, 32.