† ˈcrassous,a.Obs.rare. [f. L. crass-us crass + -ous: cf. F. crasseux (in Paré 16th c.), dirty, sordid.] = crass a. 1708Motteux Rabelais v. xxii. (1737) 100 The Servitude of crassous Ignorance.1788H. Clarke School Candidates (1877) 20 The imputation of crassous ignorance.