Tougher GRE-leaning words.
Abate
Become less intense.
Aberrant
Deviating from the normal.
Abscond
Leave secretly to avoid detection.
Abstain
Restrain from doing something.
Acrimony
Bitterness in speech/behavior.
Admonish
Warn or reprimand firmly.
Aesthetic
Concerned with beauty.
Alacrity
Eager willingness.
Anomaly
Something different from what is expected.
Apathy
Lack of interest or emotion.
Assuage
Make milder; soothe.
Audacious
Bold; daring.
Austere
Severe; strict; bare.
Capricious
Impulsive; unpredictable.