A noun used to describe the state of mind a person is in, after the intake of drugs has an ecstasy affect on your brain.
After a guy has just taken drugs he becomes somewhat retarded in the head. often acting weird and screaming words like "timmy" or "bonno" this is what a bonno is.
by Imogen-Joanne-jonathan-carr June 19, 2009
Someone who is muscular. Someone who is cool. In other words, something or someone that is gnarly.
The waves were bonno.
by Ducky007 January 04, 2008