a smart alec/aleck
One who makes jokes and uses sarcasm in an attempt to seem witty, but instead is deemed annoying. Also seen as "smart alec." I'd had enough of that smart aleck's wisecracks, so I left the party early.
An impudent or obnoxiously self-assertive individual, a wise guy, as in New teachers often have a hard time coping with the smart alecks in their classes. This expression, dating from the mid-1800s, probably alluded to a person of this description who was named Alec or Alexander, but his identity has been lost.
a smart alecBRITISH or
a smart aleck
A smart alec or a smart aleck is someone who is very clever and who is often able to answer questions in a clever way. Note: People sometimes spell `alec' and `aleck' with capital initials, as names. They've got some smart alec of a lawyer from London to oppose bail. Note: You can use smart alec and smart aleck before a noun. I hate smart-aleck kids who talk like dictionaries. Note: You use this expression to show that you find someone annoying. Note: Alec or Aleck is a shortened form of the name Alexander.
smart alec (or aleck)a person considered irritating because they know a great deal or always have a clever answer to a question.
From the male personal name Alec, a short form of Alexander.