shrew

in theory nonsexist, in practice "shrew" is reserved for women. Consider using instead grouch, grumbler, crosspatch, faultfinder, complainer, pain in the neck, nitpicker, troublemaker, bad-tempered/peevish/cranky/petulant person. Writer and editor Ethel Strainchamps has pointed out that the root of "shrew" is the same as that of "shrewd," which is more commonly used of men.