1660s, from Low German smuggeln or Dutch smokkelen "to transport (goods) illegally," apparently a frequentative formation of a word meaning "to sneak" (from Proto-Germanic *smuganan; cognates: Dutch smuigen "to eat secretly;" Swedish smyg "a lurking-hole," Danish smughandel "contraband trade," Norwegian smjuga, Old English smeogan "to creep"), perhaps literally "to slip (contraband through)," from Proto-Germanic *(s)muk- (see smock).