| A | B |
| hypochondriac | a person suffering from abnormal anxiety about his or her health; one who imagines that he or she has symptoms of various diseases |
| idiomatic | characteristic of a particular language |
| idyll | a short description of peaceful country life; a scene suitable for such a work |
| imbibe | to drink; to drink in or to absorb |
| immemorial | reaching back beyond the bounds of memory; extremely old |
| imperious | domineering; overbearing; arrogant |
| impetuous | moving with great force or speed; acting hastily, rashly, or on impulse |
| impotent | powerless; uanble to act effectively |
| impregnable | not capable of being conquered or overcome; able to resist attack or capture |
| impromptu | without previous thought or preparation; spontaneous |