Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† graecisso (-izo), āre, v. n., = Γραικίζω, to imitate the Greeks, to adopt a Grecian manner or tone: atque adeo hoc argumentum graecissat; tamen Non atticissat; verum sicelissat, Plaut. Men. prol. 7; v. Ritschl ad h. l.: graecizat, Consent. 1063 P.