1932, alteration of dialectal verb smouch "to kiss" (1570s), possibly imitative of the sound of kissing (compare German dialectal schmutzen "to kiss"). An earlier alteration produced smudge (v.) "to kiss, caress" (1844). Related: Smooched; smooching. As a noun by 1942.
smokestack
smokey
Smokey Bear
smoky
smolder
smooch
smoochy
smooth
smoothie
smoothly
smoothness