| ingratiate | Gain favor with someone by deliberate efforts | |
| inimitable | So good or unusual as to be impossible to copy; unique. | |
| innate | Inborn; natural | |
| inordinate | Exceeding reasonable limits; immoderate | |
| inscrutable | Impossible to understand or interpret | |
| insipid | Lacking flavor; dull; not at all stimulating | |
| insolence | Rude and disrespectful behavior | |
| insular | Ignorant of or uninterested in cultures, ideas, or peoples outside one's own experience | |
| integrate | To combine one thing with another to form a whole | |
| interloper | A person who becomes involved in a place or situation where they are not wanted or are considered not to belong | |