The noun excuse has 3 senses (first 1 from tagged texts)
1. (10) excuse, alibi, exculpation, self-justification -- (a defense of some offensive behavior or some failure to keep a promise etc.; "he kept finding excuses to stay"; "every day he had a new alibi for not getting a job"; "his transparent self-justification was unacceptable")
2. excuse -- (a note explaining an absence; "he had to get his mother to write an excuse for him")
3. apology, excuse -- (a poor example; "it was an apology for a meal"; "a poor excuse for an automobile")
Overview of verb excuse
The verb excuse has 6 senses (first 4 from tagged texts)
1. (2) excuse, pardon -- (accept an excuse for; "Please excuse my dirty hands")
2. (2) excuse, relieve, let off, exempt -- (grant exemption or release to; "Please excuse me from this class")
3. (2) excuse, explain -- (serve as a reason or cause or justification of; "Your need to sleep late does not excuse your late arrival at work"; "Her recent divorce may explain her reluctance to date again")
4. (1) apologize, apologise, excuse, justify, rationalize, rationalise -- (defend, explain, clear away, or make excuses for by reasoning; "rationalize the child's seemingly crazy behavior"; "he rationalized his lack of success")
5. excuse, beg off -- (ask for permission to be released from an engagement)
6. excuse, condone -- (excuse, overlook, or make allowances for; be lenient with; "excuse someone's behavior"; "She condoned her husband's occasional infidelities")