1. (人)虚情假意的，虚与委蛇的
If you describe someone as unctuous, you are critical of them because they seem to be full of praise, kindness, or interest, but are obviously insincere.

2. （食品、饮料）含乳脂的，油的，油腻的
If you describe food or drink as unctuous, you mean that it is creamy or oily.

1. unpleasantly and excessively suave or ingratiating in manner or speech

e.g. buttery praise
gave him a fulsome introduction
an oily sycophantic press agent
oleaginous hypocrisy
smarmy self-importance
the unctuous Uriah Heep
soapy compliments

Synonym: butteryfulsomeoilyoleaginoussmarmysoapy