Definition of wise guy in US English:

wise guy

noun

informal
  • 1North American A person who speaks and behaves as if they know more than others.

    • ‘Some wise guy had a tape measure with him and took a reading.’
    • ‘He continued to play numerous characters alternating between lead and supporting roles in various comedy flicks usually seen as a loveable slob, a bumbling schemer or an overbearing wise guy.’
    • ‘Well alright mister wise guy, if you're so clever you tell us what colour it should be!’
    • ‘He was no wise guy or rebel, but rather was on his best behavior, knowing that his commercial future and fame were on the line, and that he would need to appeal to an older demographic with the passing of time.’
    • ‘Well, I have felt he's been a wise guy for some time and it certainly appears he's being that way now with his interlocutors.’
  • 2US A member of the Mafia.

    • ‘Could be any inner-city gang member or wise guy.’
    • ‘While other kids were flipping burgers, he was hiring himself out to local wise guys as muscle or masterminding his own bizarre capers.’
    • ‘His mob family is undergoing an anarchic growth spurt, as wise guys jailed in the 1980s are suddenly free to get back in the game.’
    • ‘In my mind, I pictured him to be a little Italian wise guy, like the mafia hit man that's always the squealer on someone in those old movies.’
    • ‘Jimmy is an ex-con and small-time wise guy running a grocery business.’

Pronunciation

wise guy

/ˈwaɪz ˌɡaɪ//ˈwīz ˌɡī/