Synonyms and related words :
Tartar, bear, bellyacher, complainant, complainer, crab, crank, croaker, crosspatch, dragon, faultfinder, feist, fire-eater, frondeur, fury, griper, grizzly bear, grouch, grouser, growler, grumbler, hothead, hotspur, kicker, kvetch, malcontent, murmurer, mutterer, querulous person, reactionary, reactionist, rebel, sourpuss, ugly customer, whiner