MOST UNCTUOUS is an adjective used to describe someone or something that is excessively or unpleasantly flattering. It can also be used to describe something that is overly smooth or greasy. The two crossword solutions for this term are SMARMIEST and OILIEST. SMARMIEST is a 9-letter word that describes someone who is excessively ingratiating or obsequious. OILIEST is a 7-letter word that describes something that is excessively smooth or greasy.