| Term | Definition |
| misogamy | hatred of marriage |
| misogynist | hater of women |
| missile | object to be thrown or projected |
| missive | letter |
| mite | very small object or creature; small coin |
| mitigate | lessen in intensity; moderate ; appease |
| mnemonic | pertaining to memory |
| mobile | movable; not fixed |
| mock | ridicule; imitate often in derision |
| mode | prevailing style; manner; way of doing something |
| modicum | limited quantity |
| modish | fashionable |
| modulate | tone down in intensity; regulate; change from one key to another |
| mogul | powerful person |
| molecule | the smallest particle (one or more atoms) of a substance that has all the properties of that substance |
| mollify | soothe |
| mollycoddle | pamper; indulge excessively |
| molt | shed or cast off hair or feathers |
| molten | melted |
| momentous | very important |
| monarchy | government under a single ruler |
| monastic | related to monks or monasteries; removed from worldly concerns |
| monetary | pertaining to money |
| monochromatic | having only one color |
| monolithic | solidly uniform; unyielding |
| monotheism | belief in one God |
| monotony | sameness leading to boredom |
| monumental | massive |
| moodiness | fits of depression or gloom |
| moratorium | legal delay of payment; suspension of ongoing or planned activity |
| morbid | given to unwholesome thought; moody; characteristic of disease |
| mordant | biting; sarcastic; stinging |
| mores | conventions; moral standards; customs |
| moribund | dying |
| morose | ill-humored; sullen melancholy |
| mortician | undertaker; One whose business is to arrange for the burial or cremation of the dead and assist at the funeral rites and who is usually an embalmer |
| mortify | humiliate; punish the flesh |
| mosaic | picture made of small colorful inlaid tiles |
| mote | small speck |
| motif | theme |
| motility | ability to move spontaneously |
| motley | multicolored; mixed |
| mottled | blotched in coloring; spotted |
| mountebank | charlatan; boastful pretender |
| muddle | confuse; mix up |
| muggy | warm and damp |
| mulct | defraud a person of something |
| multifarious | varied; greatly diversified |
| multiform | having many forms |
| multilingual | having many languages |
| multiplicity | state of being numerous |
| mundane | worldly as opposed to spiritual; everyday |
| munificent | very generous |
| mural | wall painting |
| murky | dark and gloomy |
| muse | ponder; To be absorbed in one's thoughts; engage in meditation. |
| musky | having the odor of musk |
| muster | gather; assemble |
| musty | stale; spoiled egg |
| mutability | ability to change in form; fickleness |
| muted | silent; muted; toned down |
| mutilate | maim |
| mutinous | unruly; rebellious |
| myopic | nearsighted; lacking foresight |
| myriad | very large number |
| nadir | lowest point |
| naivete | quality of being unsophisticated; simplicity; artlessness; gullibility |
| narcissist | A conceited, self-centered person |
| narrative | related to telling story |
| nascent | incipient; coming into being |