making and accepting apologies

I. ex‧cuse1 S1 /ɪkˈskjuːz/ BrE AmE verb [transitive]
[Word Family: verb: excuse; noun: excuse; adverb: inexcusably; adjective: excusable ≠ inexcusable]
[Date: 1400-1500; Language: Old French; Origin: excuser, from Latin excusare, from causa 'cause, explanation']
1. excuse me spoken
a) used when you want to get someone’s attention politely, especially when you want to ask a question:
Excuse me, can you tell me the way to the museum please?
b) used to say that you are sorry for doing something rude or embarrassing:
Oh, excuse me. I didn’t know anyone was here.
c) used to ask someone politely to move so that you can walk past:
Excuse me, could I just squeeze past?
d) used to politely tell someone that you are leaving a place:
Excuse me a moment. I’ll be right back.
e) used when you disagree with someone but want to be polite about it SYN I’m sorry:
Excuse me, but I don’t think that’s what he meant at all.
f) American English used to show that you disagree with someone or are very surprised or upset by what they have just said:
‘You’re going to pay, right?’ ‘Excuse me?’
g) especially American English used to ask someone to repeat something that they have just said SYN pardon me:
‘What time is it?’ ‘Excuse me?’ ‘I asked you what time it is.’
2. FORGIVE to forgive someone for doing something that is not seriously wrong, such as being rude or careless:
I’ll excuse you this time, but don’t be late again.
Please excuse my bad handwriting.
excuse somebody for (doing) something
Please excuse me for being so late today.
Smith can be excused for his lack of interest in the course (=his lack of interest is reasonable).
REGISTER
In informal situations, people often say sorry about …, sorry for doing ... or sorry I … rather than asking someone to excuse something:
▪ Sorry about my handwriting.
▪ Sorry for being so late. OR Sorry I’m so late.
3. FROM A DUTY [usually passive] to allow someone not to do something that they are supposed to do
excuse somebody from (doing) something
Can I be excused from swimming today? I have a cold.
4. EXPLAIN to be or give a good reason for someone’s careless or offensive behaviour:
Nothing can excuse that kind of rudeness.
5. FROM A PLACE to give someone permission to leave a place:
May I please be excused from the table?
6. excuse yourself to say politely that you need to leave a place:
Richard excused himself and went to his room.
7. excuse me (for living)! spoken used when someone has offended you or told you that you have done something wrong

Oxford Advanced Learner's Dictionary

Cambridge Advanced Learner's Dictionary

Collins COBUILD Advanced Learner’s English Dictionary

excuse
excuses, excusing, excused
(The noun is pronounced [ɪkskju͟ːs]. The verb is pronounced [ɪkskju͟ːz].)
1) N-COUNT: oft N for n/-ing, N to-inf An excuse is a reason which you give in order to explain why something has been done or has not been done, or in order to avoid doing something.
  It is easy to find excuses for his indecisiveness...
  Once I had had a baby I had the perfect excuse to stay at home...
  If you stop making excuses and do it you'll wonder what took you so long.
  Syn:
  justification
  ●
  PHRASE: v-link PHR, oft PHR for n/-ing If you say that there is no excuse for something, you are emphasizing that it should not happen, or expressing disapproval that it has happened. (disapproval)
  There's no excuse for behaviour like that...
  Solitude was no excuse for sloppiness.
2) VERB To excuse someone or excuse their behaviour means to provide reasons for their actions, especially when other people disapprove of these actions.
  [V n by -ing] He excused himself by saying he was `forced to rob to maintain my wife and cat'...
  [V n] That doesn't excuse my mother's behaviour.
  Syn:
  justify
3) VERB If you excuse someone for something wrong that they have done, you forgive them for it.
  [V n for n/-ing] Many people might have excused them for shirking some of their responsibilities. [Also V n, V n n]
  Syn:
  forgive
4) VERB: usu passive If someone is excused from a duty or responsibility, they are told that they do not have to carry it out.
  [be V-ed from n/-ing] She is usually excused from her duties during the school holidays...
  [be V-ed n] She was excused duties on Saturday.
5) VERB If you excuse yourself, you use a phrase such as `Excuse me' as a polite way of saying that you are about to leave.
  [V pron-refl] He excused himself and went up to his room.
6) CONVENTION (formulae) You say `Excuse me' when you want to politely get someone's attention, especially when you are about to ask them a question.
  Excuse me, but are you Mr Honig?
  Syn:
  pardon me
7) CONVENTION (formulae) You use excuse me to apologize to someone when you have disturbed or interrupted them.
  Excuse me interrupting, but there's a thing I feel I've got to say.
8) CONVENTION (politeness) You use excuse me or a phrase such as if you'll excuse me as a polite way of indicating that you are about to leave or that you are about to stop talking to someone.
  `Excuse me,' she said to Jarvis, and left the room...
  Now if you'll excuse me, I've got work to do.
9) CONVENTION You use excuse me, but to indicate that you are about to disagree with someone. [mainly BRIT]
  Excuse me, but I want to know what all this has to do with us.
10) PHRASE (formulae) You say excuse me to apologize when you have bumped into someone, or when you need to move past someone in a crowd.
  Saying excuse me, pardon me, Seaton pushed his way into the crowded living room.
  Syn:
  sorry
11) CONVENTION (formulae) You say excuse me to apologize when you have done something slightly embarrassing or impolite, such as burping, hiccupping, or sneezing.
  Syn:
  pardon me
12) CONVENTION (formulae) You say `Excuse me?' to show that you want someone to repeat what they have just said. [AM](in BRIT, usually use pardon, sorry)

Merriam-Webster's Advanced Learner's Dictionary

Merriam-Webster's Advanced Learner's Dictionary:

¹ex·cuse /ɪkˈskjuːz/ verb -cus·es; -cused; -cus·ing [+ obj]
1 : to forgive someone for making a mistake, doing something wrong, etc.,
• Please excuse [=pardon] my clumsiness.
• His boss excused the mistake but told him to be more careful next time.
• Please excuse me for not calling sooner.
2 a : to say that (someone) is not required to do something
• I was excused from jury duty.
• The teacher excused the class from homework that day.
b : to allow (someone, such as a child) to leave
• I've finished my dinner. May I (please) be excused? [=allowed to leave the dinner table]
3 : to be an acceptable reason for (something) : justify
• Nothing can excuse that kind of rudeness.
• Her father's illness excused her absence.
excuse me
✦Excuse me is used as a polite way of starting to say something. It can be used when you are interrupting someone, trying to get someone's attention, or disagreeing with someone.
• Excuse me, but may I say something?
• Excuse me, but do you mind if I shut the window?
• Excuse me, do you know where I can find Maple Street?
• Excuse me, but I don't think those figures are entirely accurate. It is also used as a polite apology for a minor fault or offense, such as laughing, coughing, or burping, and, in U.S. English, for getting in someone's way or bumping into someone.
• Oh, excuse me. [=pardon me, I beg your pardon] I didn't notice you standing there. The phrase is also used, especially in U.S. English, as a polite way of asking someone to repeat something.
• Excuse me? [=pardon me?; I beg your pardon?] I didn't hear the last part of what you were saying. In informal use, excuse me is often used in an annoyed way when someone has suggested that you have done something wrong and you do not feel that you have.
• “You were supposed to be home an hour ago.” “Well, excuse me! I had to fix a flat tire.”
excuse yourself : to say politely that you have to leave
• Excusing himself, he quickly rose from the table and left the room.
- ex·cus·able /ɪkˈskjuːzəbəl/ adj
• Such minor errors are excusable.