Raise trainee, terribly fit (4)
I believe the answer is:
lift
'raise' is the definition.
('lift' can be a synonym of 'raise')
'trainee terribly fit' is the wordplay.
'trainee' becomes 'l'.
'terribly' is an anagram indicator.
'fit' with letters rearranged gives 'ift'.
'l'+'ift'='LIFT'
(Other definitions for lift that I've seen before include "encouragement" , "Raise - hoist" , "Means of access to different floors" , "It's an elevator in USA" , "Raise; elevator" .)