| A | B |
| agnostic | one who believes that it is impossible to know whether there is a God |
| amoral | not involving questions of right or wrong; without moral quality; neither moral nor immoral. |
| amorphous | lacking definite form; having no specific shape; formless: the amorphous clouds. |
| anomaly | someone or something that is abnormal or does not fit in |
| anonymous | not named or identified |
| abacterial | without bacteria |
| apathy | lack of passion, emotion, or excitement. |
| atheist | a person who believes that God does not exist |
| atrophy | decrease in size or wasting away of a body part or tissue |
| atypical | not typical; not conforming to the type; irregular; abnormal |