KnuckleSprout Share definition Flag KnuckleSprout is defined as an insult to another for stealing or offending others or who has lost a few brain cells in a moment. You are such a knucklesprout, Jimmy! KnuckleSprout by 6q1 May 28, 2022 0 0 Get merch Get the KnuckleSprout mug. Buy Now — $32.95 See more merch