Definition
Oleaginousness is similar to oiliness, describing something that has the qualities of oil, often used figuratively to mean excessively smooth, flattering, or insincere. It implies a quality that's unctuous and perhaps manipulative. Think of a politician who's overly friendly and agreeable, but you don't quite trust them. It's like they're trying too hard to please you, and it feels fake. Oleaginousness is a fancy way of saying someone is being too slick for their own good. It often carries a negative connotation.