| Term | Definition |
| Hegemony | the domination of one state or group over its allies |
| Hermetic | tightly sealed |
| Heterogeneous | composed of unlike parts; different; diverse |
| Hoary | very old; whitish or gray from age |
| Homogeneous | of a similar kind |
| Husband | to manage economically; to use sparingly |
| Hyperbole | purposeful exaggeration for effect |
| Iconoclast | one who opposes established beliefs, customs, and institutions |
| Idiosyncrasy | peculiarity of temperament; eccentricity |
| Ignoble | having low moral standards; not noble in character; mean |
| Imbue | to infuse, dye, wet, or moisten |
| Impasse | blocked path; dilemma with no solution |
| Impecunious | poor; having no money |
| Imperturbable | not capable of being disturbed |
| Impervious | impossible to penetrate; incapable of being affected |
| Impetuous | quick to act without thinking |
| Impious | not devout in religion |
| Implacable | unable to be calmed down or made peaceful |
| Imprecation | a curse |
| Impugn | to call into question; to attack verbally |
| Incarnadine | blood-red in color |
| Inchoate | not fully formed; disorganized |
| Inculcate | to teach; impress in the mind |
| Indolent | habitually lazy or idle |
| Inexorable | inflexible; unyielding |
| Ingenuous | showing innocence or childlike simplicity |
| Ingrate | ungrateful person |
| Ingratiate | to gain favor with another by deliberate effort; to seek to please somebody so as to gain an advantage |
| Inimical | hostile; unfriendly |
| Iniquity | sin; evil act |
| Innocuous | harmless |
| Inquest | an investigatin; an inquiry |
| Insipid | lacking interest or flavor |
| Insurrection | rebellion |
| Inter | to bury |
| Interregnum | period between reigns |
| Intractable | not easily managed or manipulated |
| Intransigent | uncompromising; refusing to be reconciled |
| Latent | potential that is not readily apparent |
| Laud | to give praise; to glorify |
| Lavish | extremely generous or extravagant; giving unsparingly |
| Leery | suspicious |
| Languid | lacking energy; indifferent |
| Lapidary | relating to precious stones or the art of cutting them |
| Larceny | theft of property |
| Largess | generous giving (as of money) to others who may seem inferior |
| Lassitude | a state of diminished energy |
| Legerdemain | trickery |
| Lethargic | acting in an indifferent or slow, sluggish manner |
| Levity | an inappropriate lack of seriousness; overly casual |