Larrikin

n.
  1. A rowdy street loafer; a rowdyish or noisy ill-bred fellow; a hoodlum; -- variously applied, as to a street blackguard, a street Arab, a youth given to horse-play, etc.

Larrikin is often popularly explained by the following anecdote (which is without foundation): An Irish policeman at Melbourne, on bringing a notorious rough into court, was asked by the magistrate what the prisoner had been doing, and replied, “He was a-larrikin' [i. e., a-larking] about the streets.”