sign off phrasal verb ( see also ↑ sign )
1 . informal to end a radio or television programme by saying goodbye
2 . to write your final message at the end of an informal letter:
It’s getting late, so I’ll sign off now. Love, John.
3 . sign somebody off British English if a doctor signs someone off, he or she gives them a note saying that they are ill and not able to work:
For the last month, she has been signed off sick from work.
4 . sign something ↔ off British English , sign off on something American English to show that you approve of a plan or that something is finished by signing an official document:
Major repainting work now needs to be signed off by a qualified engineer.