| Term | Definition |
| macabre | Having death as a subject; speaking about the gruesome |
| macrocosm | The whole universe; a large-scale reflection of part of a greater world |
| malaise | A feeling of unease, worry, or depression |
| malapropism | The accidental, comical use of a word that resembles the one intended, but has a different or contradictory meaning |
| malediction | A curse; a wish of evil upon another |
| malevolent | Exhibiting ill will; intending harm upon others |
| malfeasance | Wrongdoing or misconduct, esp. by a public official |
| malleable | Easily influenced or shaped, capable of being altered by force |
| mannered | Artificial or affected in character |
| maverick | An independent individual who doesn't follow along with the group |
| mawkish | Sickly emotional; sickening taste |
| megalomania | Obsession with great, grand performance |
| mellifluous | Having a smooth, rich flow |
| microcosm | A small-scale representation of a larger object or system |
| milieu | The physical or social setting where something is formed or occurs; environment |
| misanthrope | A person who despises or distrusts mankind |
| misnomer | An error in identifying a person or place |
| missive | A written note or letter |
| mitigate | To make less severe |
| modicum | A small portion; limited quantity |
| mollify | A soothe in temper or emotions |
| mordant | Biting or sarcastic in manner or style |
| mores | Fixed, standard customs or manners; moral attitudes |
| morose | Dour; sullen |
| mote | A small particle or speck |
| mutability | The characteristic of being capable of change; open or exposed to change |
| myopic | Lacking foresight; having a narrow view or perspective |