Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
ŏpĭcus, a, um, adj. [a fuller form for Opsus, Obscus, and Oscus, lit. Oscan; cf. Paul. ex Fest. p. 188 Müll.; hence, transf.], clownish, rude, stupid, ignorant, foolish (not in Cic.): (Graeci) nos quoque dictitant barbaros et spurcius nos quam alios opicos appellatione foedant, M. Cato ap. Plin. 29, 1, 7, § 14: ut nostri opici putaverunt, Gell. 13, 9, 4: chartae, rough, coarse, unpolished, Aus. Prof. 22: amica, Juv. 6, 454: opici mures, barbarians of mice, that gnaw books, id. 3, 207.