A bonkers monkey. A monkey that is bonkers (mad). Good-natured term used when either 'monkey' (as in "you cheeky monkey") or 'bonkers' (as in "you must be bonkers") isn't strong enough on its own.
Rhymes with 'dOnkey', as opposed to 'mUnkey'.
Invention credited to, and first recorded use by, Afira Khan, London UK 2006.
A term of friendly abuse: "Oh, you BONKEY!"