BUTTERIEST
Scrabble letter values: B3U1T1T1E1R1I1E1S1T1 = 12
Definition
BUTTERIEST is the superlative of BUTTERY.
adjective BUTTERY: unpleasantly and excessively suave or ingratiating in manner or speech.
Synonyms of BUTTERY: fulsome, oily, oleaginous, smarmy, soapy, unctuous