In Super Smash Bros. Brawl, or any Smash Bros.
game, there comes a point where a Smasher can't
smash at their best. Your moves become stiff and your reaction
time decreases.
(Derived from the term 'Writer's Block', where a writer comes to a point where the mind boggles and cannot create any ideas for his/her stories)
Similar definitions: brawler's block, fighter's block, cock block
P1: Dude, you
suck.
P2: Curse this damn Smasher's
Block.
P1: Right.
P2: I'ma get you when I can play
better.
P1: We'll see dude. We'll see.