Origin: Latin suffix -ous
Unctuous has 2 different meanings across 1 category:
unpleasantly and excessively suave or ingratiating in manner or speech
"buttery praise"
"gave him a fulsome introduction"
"an oily sycophantic press agent"
"oleaginous hypocrisy"
"smarmy self-importance"
"the unctuous Uriah Heep"
"soapy compliments"
Oily or greasy.