look up any word, like ratchet:
 
1.
A HUGE THICK VEINY COCK
Never swing at a woman...Unless you swingin' yo' MONKEY ARM.
by CAPTAIN COCKMEAT May 19, 2011
 
2.
A visual display of frustration or disappointment where you hang your head and raise your arms over your head and wave them back and forth in a monkey-like manner.
I could see John was having a bad day on the golf course when he went full Monkey Arms after yet another bad short.
by Jake1675 May 30, 2013