- noun violent quarrelling or disagreement
- noun disorderly behaviour leading to violence
- adjective wonderful, excellent. This probably ephemeral term was recorded among teenagers in New york and California in the late 1980s. It is probably based on a misunderstanding or deliberate shifting in the meaning of the earlier British term.
- noun aggravation. Originally the slang term was a euphemism for threatened or actual violence, offered typically by skinheads, although it is not clear whether they or their (typically hippy) victims first adopted the shortened form at the end of the 1960s. (Whichever is the case, the word is a derivation of aggravation in its colloquial sense as used by police officers and criminals since the 1950s.) Aggro, like bother, is a typical example of the use of menacing understatement in British working-class slang. The word was soon taken up by other users and, in informal English, has now reverted to something like its original unspecific meaning of annoyance or trouble. In Australian usage aggro can be used as an adjective, as in ‘I guess I was a bit aggro last night’.