A device used to make galloping sounds when cut into two halves and hollowed out.
SOLDIER #1:
What? Ridden on a horse?
ARTHUR:
Yes!
SOLDIER #1:
You're using coconuts!
ARTHUR:
What?
SOLDIER #1:
You've got two empty halves of coconut and you're bangin' 'em together.
Essentially a meaningless insult. Can be used in place of 'idiot,' 'moron,' or 'dumbass;' but the meaning doesn't matter, only the fact that it's an insult.
Derived from the inverse of "growths." Just because it sounded funny.