The term 'too smooth' can be described by the crossword solutions of OILY (4 letters), PAT (3 letters), and GLIB (4 letters). OILY refers to something that is covered in or saturated with oil, which can give it a slippery texture. PAT is an adjective meaning done in a quick, careless way, often without thought or effort. GLIB is an adjective meaning speaking or spoken in a smooth, unconvincing way, often as a result of insincerity or superficial knowledge. Together, these words describe someone who is too smooth, meaning they are slick, quick to talk, and unconvincing.