Definitions of excuse:

• noun:   a note explaining an absence

  Example: "He had to get his mother to write an excuse for him"

• noun:   a defense of some offensive behavior or some failure to keep a promise etc.

  Example: "He kept finding excuses to stay"

• noun:   a poor example

  Example: "A poor excuse for an automobile"

• verb:   excuse, overlook, or make allowances for; be lenient with

  Example: "Excuse someone's behavior"

• verb:   serve as a reason or cause or justification of

  Example: "Your need to sleep late does not excuse your late arrival at work"

• verb:   grant exemption or release to

  Example: "Please excuse me from this class"

• verb:   ask for permission to be released from an engagement
• verb:   accept an excuse for

  Example: "Please excuse my dirty hands"

• verb:   defend, explain, clear away, or make excuses for by reasoning