| Term | Definition |
| histrionic | a deliberate display of emotion for effect |
| solicitous | showing hovering attentiveness |
| antithesis | the absolute opposite |
| anxiety | intense uneasiness |
| apathetic | lacking concern, emotion |
| apocryphal | fictitious, false, wrong |
| appalling | inspiring shock, horror, disgust |
| appease | to calm, satisfy |
| appraise | to assess the worth or value of |
| apprehend | to seize, arrest/to perceive, understand, grasp |
| approbation | praise |
| appropriate | to take, make use of |
| aquatic | relating to water |
| arable | suitable for growing crops |
| arbiter | one who can resolve a dispute, make a decision |
| arbitrary | based on factors that appear random |
| arbitration | the process or act of resolving a dispute |
| arboreal | of or relating to trees |
| arcane | obscure, secret, known only by a few |
| archaic |  of or relating to an earlier period in time, outdated |
| archetypal | the most representative or typical example of something |
| ardor | extreme vigor, energy, enthusiasm |
| arid | excessively dry |
| arrogate | to take without justification |
| artifact | a remaining piece from an extinct culture or place |
| artisan | a craftsman |
| ascertain | to perceive, learn |
| ascetic | practicing restraint as a means of self-discipline, usually religious |
| ascribe | to assign, credit, attribute to |
| aspersion | a curse, expression of ill-will |
| aspire | to long for, aim toward |
| assail | to attack |
| assess | to evaluate |
| assiduous | hard-working, diligent |
| assuage | to ease, pacify |