Eyy m9 remember that one time after soundwave, m9? I nearly fucken died from having sex with that marsupial on top of a moving train moving through alice springs, eyy that was so fucken alpha, m9.
beretta M9 9mm semi-auto pistol, a peice of shit,..
a peice of metal, useless for the most part, more deadly when thrown then when fired, (or when attemping to fire anyway,...)
When a newb tries to be a smart arse when calling you mate abbreviated as m9 instead of m8 just to piss you off. More commonly when playing an FPS such as Battlefield or CoD.