| inveigh | To speak or write about something with great hostility | |
| intrusive | Causing disruption or annoyance through being unwelcome or uninvited. | |
| intrinsic | Belonging naturally; essential | |
| intrepid | Very brave, fearless, unshakable | |
| intimate | Having a close, personal relationship or being closely acquainted | |
| interloper | A person who becomes involved in a place or situation where they are not wanted or are considered not to belong | |
| integrate | To combine one thing with another to form a whole | |
| insular | Ignorant of or uninterested in cultures, ideas, or peoples outside one's own experience | |
| insolence | Rude and disrespectful behavior | |
| insipid | Lacking flavor; dull; not at all stimulating | |