Getting fit (8)
I believe the answer is:
becoming
I believe this clue is a double definition.
'getting' is the first definition.
('become' can be a synonym of 'get')
'fit' is the second definition.
(thesaurus)
(Other definitions for becoming that I've seen before include "Turning into - lovely" , "fetching" , "Developing into" , "attractive" , "Comme il faut" .)