1. Of or relating to oil.
2. Falsely or smugly earnest; unctuous: oleaginous flattery. See synonyms at unctuous.

[From Middle English oliaginose and from French oléagineux (from Old French), both from Latin oleāginus, of the olive tree, from olea, olive tree, alteration (influenced by oleum, olive oil) of olīva; see olive.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.