WordNet sense 1 (a retailer of meat):

meatman

WordNet sense 2 (a person who slaughters or dresses meat for market):

slaughterer

WordNet sense 3 (someone who makes mistakes because of incompetence):

blunderer, botcher, bumbler, bungler, fumbler, stumbler, fuckup, sad sack

WordNet sense 4 (kill (animals) usually for food consumption):

slaughter