| Term | Definition |
| hibernal | wintry |
| hibernate | sleep throughout the winter |
| hierarchy | arrangement by rank or standing; authoritarian body divided into ranks |
| hieroglyphic | picture writing |
| hilarity (adj.) hilarious | boisterous mirth |
| hindmost | furthest behind |
| hindrance | block; obstacle |
| hinterlands | back country |
| hireling | one who serves for hire (usually used contemptuously) |
| hirsute | hairy |
| histrionic | theatrical |
| hoard | stockpile; accumulate for future use |
| hoary | white with age |
| hoax | trick; practical joke |
| holocaust | destruction by fire |
| holster | pistol case |
| homage | honor; tribute |
| homeostasis | tendency of a system to maintain relative stability |
| homespun | domestic; made at home |
| homily | sermon; serious warning |
| homogeneous | of the same kind |
| hone | sharpen |
| hoodwink | deceive; delude |
| horde | crowd |
| hortatory | encouraging; exhortive |
| horticulture | pertaining to cultivation of gardens |
| hostility | unfriendliness; hatred |
| hovel | shack; small, wretched house |
| hover | hang about; wait nearby |
| hubbub | confused uproar |
| hubris | arrogance; excessive self-conceit |
| hue | color; aspect |
| hue and cry | outcry |
| humane | marked by kindness or consideration |
| humdrum | dull; monotonous |
| humid | damp |
| humility | humbleness of spirit |
| hummock | small hill |
| humus | substance formed by decaying vegetable matter |
| hurtle | crash; rush; to move swiftly and with great force |
| husband (v) | use sparingly; conserve; save |
| husbandry | frugality; thrift; agriculture |
| hybrid | mongrel (<-- crossbred); mixed breed |
| hydrophobia | fear of water; rabies |
| hyperbole | exaggeration; overstatement |
| hypercritical | excessively exacting |
| hypochondriac | person unduly worried about his health; worrier without cause about illness |
| hypocritical | pretending to be virtuous; deceiving |
| hypothetical | based on assumptions or hypotheses; supposed |
| ichthyology | study of fish |
| icon | religious image; idol |
| iconoclastic | attacking cherished traditions |
| ideology | system of ideas characteristic of a group or culture |
| idiom | expression whose meaning as a whole differs from the meanings of its individual words; |
| idiosyncrasy | individual trait, usually odd in nature; eccentricity |
| idolatry | worship of idols; excessive admiration |
| idyllic | charmingly carefree; simple |
| igneous | produced by fire; volcanic |
| ignite | kindle; light |
| ignoble | unworthy; not noble |
| ignominy | deep disgrace; shame or dishonor |
| illicit | illegal |
| illimitable | infinite |
| illuminate | brighten; clear up or make understandable; enlighten |
| illusion | misleading vision |
| illusive | deceiving |
| illusory | deceptive; not real |
| imbalance | lack of balance or symmetry; disproportion |
| imbecility | weakness of mind |
| imbibe | drink in |
| imbroglio | complicated situation; painful or complex misunderstanding; entanglement; confused mass |
| imbue | saturate, fill |