(plural only, bodybuilding, slang) Well-developed muscles of the upper arm, especially the biceps and triceps.
2005, Joe Kita (ed.), Men's Health Best: Arms, page 6And there's still no better way to throw down the fitness gauntlet that to roll up your sleeves and unveil some powerful guns.
2010, Mark Alvisi (quote from a reader), "Mark of a Champion", Muscular Development‎47(1): 350I read in another magazine about a workout that can put a whole inch on your arms in just one day! Obviously that sounds awesome, because my guns are only 15 inches.
