The term 'overly smooth' can be described by three crossword solutions: OILY (4 letters), GLIB (4 letters), and PAT (3 letters). OILY is an adjective that describes something that is covered in or saturated with oil. GLIB is an adjective that means to be fluent and voluble in speech, often in a way that is insincere or superficial. PAT is an adjective that means done in a mechanical or perfunctory way, without thought or care. Together, these words describe someone who speaks in a slick, insincere, and mechanical manner.