(n.) One who, or that which, crushes.

KO cheese grater clincher comminutor conclusive argument death stroke deathblow end-all ender final stroke finisher finishing stroke floorer granulator grater grinder kayo kayo punch knockdown argument knockout knockout blow kominuter last dab levigator masher mill millstone mortar and pestle nutmeg grater pestle pulverizer quern quernstone quietus rock crusher roller settler shredder sockdolager steamroller stopper triturator