ex·cuse

[v. ik-skyooz; n. ik-skyoos] verb, -cused, -cus·ing, noun

–verb (used with object)

1. to regard or judge with forgiveness or indulgence; pardon or forgive; overlook (a fault, error, etc.): Excuse his bad manners.

2. to offer an apology for; seek to remove the  blame of: He excused his absence by saying that he was ill.

3. to serve as an apology or justification for; justify: Ignorance of the law excuses no one.

4. to release from an obligation or duty: to be excused from jury duty.

5. to seek or obtain exemption or release for (oneself): to excuse oneself from a meeting.

6. to refrain from exacting; remit; dispense with: to excuse a debt.

7. to allow (someone) to leave: If you’ll excuse me, I have to make a telephone call.

–noun
8. an explanation offered as a reason for being excused; a plea offered in extenuation of a fault or for release from an obligation, promise, etc.: His excuse for being late was unacceptable.

9. a ground or reason for excusing or being excused: Ignorance is no excuse.

10. the act  of excusing someone or something.

11. a pretext or subterfuge: He uses his poor health  as an excuse for evading all responsibility.

12. an inferior or inadequate specimen of something specified: That coward is barely an excuse for a man. Her latest effort is a poor excuse for a novel.

—Idiom
13. Excuse me, (used as a polite expression, as when addressing a stranger, when interrupting or disagreeing with someone, or to request repetition of what  has just been said.)