325. Anomaly, Irregularity

Anomaly: Deviation from norm
Irregularity: Unusual occurrence

326. Antediluvian, Ancient

Antediluvian: Extremely old
Ancient: Very old

327. Appease, Pacify

Pacify: Bring peace

328. Apprehensive, Anxious

Apprehensive: Uneasy about the future
Anxious: Worried

329. Arduous, Laborious

Arduous: Difficult
Laborious: Requiring effort

330. Artifice, Deception

Artifice: Clever trickery
Deception: The act of deceiving

331. Ascetic, Austere

Ascetic: Practicing strict self-denial

332. Aspersion, Slander

Aspersion: False attack
Slander: Defamation

333. Assail, Attack

Assail: Attack violently
Attack: Act aggressively

334. Assuage, Soothe

Assuage: Ease pain
Soothe: Calm

335. Audacious, Bold

Audacious: Fearlessly daring
Bold: Confident

336. Augment, Increase

Augment: Make greater
Increase: Become larger