| A | B |
| Inert | Adj: having no power to act or move; inactive |
| Inexorable | Adj: cannot be moved or influenced by persuasion or entreaty; unrelenting |
| Inscrutable | Adj: cannot be easily understood; mysterious |
| Insipid | Adj: without flavor; tasteless; dull; lifeless |
| Intrepid | Adj: without fear; brave |
| Irascible | Adj: easily angered |
| Jaundiced | Adj: Prejudiced, cynical |
| Jaunty | Adj: fashionable, stylish; carefree |
| Jettison | Verb: to throw goods overboard |
| Jingoism | Noun: extreme patriotism; favoring an aggressive, warlike foreign policy |
| Jocose | Adj: joking, humorous |
| Juggernaut | Noun: a terrible destructive or irrestible force |
| Latent | Adj: present, but not active; hidden |
| Laudable | Adj: worthy of praise; commendable |
| Lethargy | Noun: lack of energy; drowsiness, disinterest |