| altruistic | Showing a disinterested and selfless concern for the well-being of others; unselfish | |
| allusion | An indirect or passing reference to an event, person, place, or artistic work that is not elaborately discussed in the context | |
| algorithm | A process or set of rules to be followed in calculations or other problem-solving operations, especially by a computer | |
| alacrity | To feel or express strong disapproval of something | |
| aghast | Filled with horror or shock | |
| affectation | Behavior, speech, or writing that is pretentious and designed to impress | |
| affable | Friendly, good-natured, or easy to talk to | |
| aesthetic | Concerned with beauty or the appreciation of beauty | |
| aegis | The protection, backing, or support of a particular person or organization | |
| advocate | A person who publicly supports or recommends a particular cause or policy | |