Atrocious, barbaric, barbarous, brutal, merciless.
Attack, assault, infringement, intrusion, onslaught.
Attain, accomplish, achieve, arrive at, compass, reach, secure.
Attempt, endeavor, essay, strive, try, undertake.
Attitude, pose, position, posture.
Attribute, ascribe, assign, charge, impute.
Axiom, truism.
Baffle, balk, bar, check, embarrass, foil, frustrate, hamper, hinder, impede, retard, thwart.
Banter, burlesque, drollery, humor, jest, raillery, wit, witticism.
Beg, plead, press, urge.