† ˈoileous,a.Obs.rare. [irreg.f. oil + -eous: cf. oleous, the regular formation.] Full of or containing oil; oily, oleous. 1597Gerarde Herbal ii. xl. §4. 255 Thicke, fat, and oileous stalkes.1603Holland Plutarch's Mor. 659 Now is the sea fattie and oileous.