| Term | Definition |
| garrulous | talkative; given to constant, trivial talking |
| germane | relevant, pertinent; appropriate or fitting |
| gregarious | sociable, outgoing |
| gullible | credulous; naive and easily deceived or tricked |
| hackneyed | cliched, warn out by overuse |
| halcyon | calm, peaceful, tranquil; prosperous, golden |
| heinous | shocking, wicked, terrible |
| hirsuite | hairy; having a hairy covering |
| ignoble | completely lacking nobility in character or quality or purpose |
| ignominious | shameful; disgraceful |
| imminent | close in time; impending, near at hand |
| immutable | unchangeable |
| impassive | unmoved; showing no emotions |
| imperious | insisting on obedience; domineering; overbearing |
| imperturbable | calm, undisturbable |
| impervious | impenetrable, nonporous, nothing gets through it |
| impetuous | impulsive, acts without thinking |
| implacable | incapable of being pacified; can't be calmed down |
| implicit | implied, not stated outright |
| impromptu | with little or no preparation or forethought; said or done on the impulse of the moment |
| inadvertent | accidental |
| inane | silly, ridiculous |
| incessant | unceasing, without stopping |
| inchoate | not yet fully formed, rudimentary, elementary; only partially existing; incipient |
| incipient | beginning to exist or appear; inchoate |