-eous
-eous suffix of adjs. the majority of which are formed on L. adjs. in -eus ( = Gr. -eos); these are based on sbs. denoting material things and usu. have the sense ‘composed of’, as well as that of ‘of the nature of, resembling’, while the Eng. derivs. have the latter meaning only; exx. are erroneous, igneous, ligneous, vitreous, and (from scholL.) heterogeneous, homogeneous. In adoptions of F. adjs. in -eux based on sbs. in -age the suffix took this form, as in advantageous, courageous, outrageous; in hideous and piteous, -eous has replaced -ous; aqueous is isolated; in bounteous, courteous, gorgeous, plenteous, righteous other endings have been assim. to -eous; in beauteous and duteous the ending has arisen from the addition of -OUS to -te, early form of -TY2. See also -ACEOUS.