cavil, quibble

challenge, dare, defy, fight

conflict, debate, dispute, hassle, quarrel, squabble, wrangle

beef, bellyache, bitch, bleat, carp, caterwaul, complain, crab, croak, fuss, gripe, grizzle, grouch, grouse, growl, grumble, grump, holler, keen, maunder [chiefly British], moan, murmur, mutter, nag, repine, scream, squawk, squeal, wail, whimper, whine, whinge [British], yammer, yawp (or yaup), yowl

balk, gag, stick

censure, criticize, denounce

disobey, rebel, withstand

demonstrate