| A | B |
|---|
| unaccustomed | not used to something |
| unbearable | impossible to tolerate |
| undamaged | left alone; intact |
| uneventful | nothing unusual happening |
| unexpected | coming as a surprise |
| unspoiled | not changed or flawed |
| unreasonable | not acting with reason |
| untangle | to straighten out something complex |
| unsuccessful | not achieving a goal |
| unlawful | not permitted by the law |
| unconscious | unaware physically or mentally |
| uncertain | undecided |
| reform | improving something by removing faults |
| reassure | to make someone feel less anxious |
| recheck | review again |
| recycle | use again differently |
| renew | extend something |
| respond | provide an answer |
| retrace | follow route or path again |
| resume | start again |
| reheat | heat again |
| refill | replace the contents of the container |
| reveal | expose something |
| revise | give an updated version |
| illegal | forbidden by law |
| illegible | not clear enough to be read |
| illiterate | unable to read or write |
| immortal | living forever |
| immature | not fully developed |
| impatient | quickly irritated |
| imperfect | faulty |
| impossible | not able to occur |
| impure | dirty |
| inboard | with in a ship |
| inbounds | ball into play from out of bounds |
| incase | enclose |
| incomplete | unfinished |
| incorrect | wrong |
| indirect | done through others |
| indoors | within a space |
| infinite | endless in space |
| injustice | lack of fairness |
| insane | crazy |
| invisible | unable to be seen |
| irrational | not reasonable |
| irregular | not even or balanced |
| irresistible | too attractive to be resisted |
| irresponsible | not able to be counted on |
