Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
pinso (pīso), pinsi and pinsŭi, pinsum, pinsĭtum, and pistum (pisatum, Fest. p. 158 Müll.), 3 (also in Varr. R. R. 1, 63 fin., the reading is pinsatur; archaic form of the imperf. pinsibant, Enn. ap. Varr. L. L. 5, § 23 Müll.; v. Enn. p. 147 fin. Vahl.), v. a. [πίσσω, πτίσσω], to beat, pound, bray, crush: pinsunt terram genibus, Enn. ap. Diom. p. 370 P. (Ann. v. 354 Vahl.): flagro, to scourge, Plaut. Merc. 2, 3, 81: si communiter pisunt, Cato, R. R. 136: pilum, quod eo far pisunt: a quo ubi id fit dicitur pistrinum, Varr. L. L. 5, § 138 Müll.: farinam, id. ap. Non. 152, 15: uvam passam, id. R. R. 3, 16: panicum pinsitum, Col. 2, 9, 19; 6, 6, 5: pisente pilo, Plin. 18, 10, 23, § 97; 18, 10, 20, § 93: qui far pisebant, id. 18, 11, 28, § 107: o Jane, a tergo quem nulla ciconia pinsit (v. ciconia), Pers. 1, 58.