French IM slang short for 'Quoi de neuf?' or 'What's new?'. Perfect to use in order to add a little french chic (aka snob up) your conversation.
Pronounced Kwah-duh-nuhf with a french accent.
Other forms of spelling: 'Quoi de neuf?' 'Koi de neuf' or 'Koide9'
Antoine: bah salut mec koi29?
Thomas: pgc. toi?