Old hand (7)
'old hand' is the definition.
(I've seen this in other clues)
This is all the clue.
(Other definitions for pro that I've seen before include "With qualifications" , "hooker" , "In favour of; advantage" , "Of argument, say, in favour of" , "Golfer" .)
'old hand' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for veteran that I've seen before include "One with lengthy experience in service" , "he's seen a lot of service" , "Past master" , "Describing cars built before 1919, especially before 1905" , "One of great experience" .)