IPA: /ʌŋkˈtʃuəsli/
KK: /ʌŋkˈtʃuəsli/
In a way that is overly flattering or ingratiating, often to the point of being insincere.
He spoke unctuously, trying to win her favor with his exaggerated compliments.
Unctuously → It is formed from "unctus" (from Latin, meaning anointed or oily) and the suffix "-ly" (meaning in a manner of). The word describes a manner that is oily or excessively flattering, often in a way that is insincere.
Think of something that is 'oily' or 'anointed' ('unctus') to remember that 'unctuously' describes a manner that is overly flattering or smooth.