IPA: /oʊˈliːədʒɪnəsli/
KK: /oʊˈliːədʒɪnəsli/
In a way that is excessively flattering or ingratiating, often to the point of being insincere or oily.
He spoke oleaginously, trying to win her favor with his exaggerated compliments.
Oleaginously → It is formed from "oleaginous" (from Latin "oleaginus", meaning oily or greasy) and the adverbial suffix "-ly" (meaning in a manner of). The word "oleaginously" means in an oily or greasy manner.
Think of something that is 'oily' ('oleaginous') and remember that 'oleaginously' describes doing something in an oily way.
No commonly confused words.