A cocky individual who thinks he or she knows everything and is not shy about saying so. The origin of this term, an American colloquialism from the 1860s, has been lost; no one knows who that first Aleck (or Alexander) was. The adjective smart in the sense of “impudent” is much older (fifteenth century) but has died out except in this expression. Budd Schulberg used it in What Makes Sammy Run? (1941): “He’s a smart aleck. I can see already he thinks he knows more than I do.”