| acerbic | sharp and forthright, especially of a comment or style of speaking | |
| acme | The point at which someone or something is best, perfect, or most successful | |
| acquisitive | Eager to acquire and possess things especially material possessions or ideas | |
| acrimonious | Angry and bitter in tone or manner | |
| acumen | The ability to make good judgments and quick decisions, typically in a particular domain | |
| adamant | Refusing to be persuaded or to change one's mind | |
| adept | Very skilled or proficient at something | |
| adequate | Sufficient for a specific requirement; enough | |
| adhere | To stick fast or cleave, as a glutinous substance does; to become attached or united | |
| admonish | Warn or reprimand someone firmly | |