Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
proprĭo, āvi, 1 (archaic form, propriassit, proprium fecerit, Paul. ex Fest. p. 229 Müll.), v. a. [proprius-facio], to appropriate (ante- and post-class.), Cael. Aur. Tard. 5, 11; id. Acut. 1, 15 fin.