Old-timer's surgeon near to collapse (7)
I believe the answer is:
veteran
'old-timer's' is the definition.
(thesaurus)
'surgeon near to collapse' is the wordplay.
'surgeon' becomes 'vet' (I've seen this in other clues).
'to collapse' indicates anagramming the letters.
'near' is an anagram of 'eran'.
'vet'+'eran'='VETERAN'
(Other definitions for veteran that I've seen before include "Old soldier's" , "Describing cars built before 1919, especially before 1905" , "One with lengthy experience in service" , "Retired soldier" , "One long experienced" .)