oleaginous adj. + Add to list US //ˌoʊɫiˈædʒənəs// oleagi·nous SynonymsEtymology Synonyms butteryfulsomegreasyoilysebaceoussmarmysoapyunctuousOriginLA-MEDoleāginōsus→ENoleaginous Borrowed from French oléagineux, borrowed from Medieval Latin oleāginōsus (“oily”), from olea (“the olive tree or its fruit”).