polemical

aggressive, bellicose, belligerent, combative, gladiatorial, militant, pugnacious, truculent, warlike

feisty, fractious, surly

balky, contrary, ornery, perverse, restive, wayward

disobedient, froward, insubordinate, intractable, recalcitrant, refractory

hardheaded, headstrong, mulish, obdurate, obstinate, pigheaded, resistant, self-opinionated, self-willed, stubborn, unbending, uncompromising, uncooperative, unreasonable, unyielding, willful (or wilful)

acidic, bearish, bilious, cantankerous, captious, choleric, crabby, cranky, cross, disagreeable, dyspeptic, fretful, grouchy, grumpy, huffy, ill-humored, ill-natured, ill-tempered, irascible, irritable, peevish, pettish, petulant, querulous, rude, snappish, snappy, splenetic, testy, touchy, waspish

battling, fighting, warring

delicate, difficult, knotty, problematic (also problematical), spiny, thorny, ticklish, touchy, tough