1. aggravate - To make heavier, worse, or more burdensome.
2. aggravation - The fact of being made heavier or more heinous, as a crime , offense, misfortune, etc.
3. aggregate - The entire number, sum, mass, or quantity of something.
4. aggress - To make the first attack.
5. aggression - An unprovoked attack.
6. aggrieve - To give grief or sorrow to.
7. aghast - Struck with terror and amazement.
8. agile - Able to move or act quickly, physically, or mentally.
9. agitate - To move or excite (the feelings or thoughts).
10. agrarian - Pertaining to land, especially agricultural land.
11. aide-de-camp - An officer who receives and transmits the orders of the general.
12. ailment - Slight sickness.
13. airy - Delicate, ethereal.
14. akin - Of similar nature or qualities.
15. alabaster - A white or delicately tinted fine-grained gypsum.