Assimilate
To take in, to absorb, to learn thoroughly
Assuage
To pacify, to ease the pain of
Astute
Shrewd, keen in judgement
Attrition
Gradual wearing away, weakening or loss, a natural or expected decrease in numbers or size
Audacity
Boldness, recklessness
Augment
To make bigger, to add to, to increase
Auspicious
Favourable, promising, pointing to a good result
Austere
Very simple, (Used about a person) very strict, serious
Autocratic
Ruling with absolute authority, extremely bossy