Abstinent
Voluntarily not doing something, especially pleasent something that is bad for you
Abstract
Summary
Abstruse
Hard to understand;Conceal;hide
Abysmal
Extremely hopeless or wretched
Accolade
An award, An honor {generally used in plural}
Accost
To approach and speak to someone, boldly or aggressively
Acerbic
Bitter; Sour; Severe
Acquiese
To agree Passively{As spelling indicates, quiet and acquiese are related
Acrid
Harsh, Like Acid
Acrimonious
Full of Spite, Bitter, Nasty
Acumen
Keenness of Judgement, Mental Sharpness