Tailor giving girl exercises (5)
I believe the answer is:
adapt
'tailor' is the definition.
(I've seen this in another clue)
'giving girl exercises' is the wordplay.
'giving' is a charade indicator (letters next to each other).
'girl' becomes 'ada' (girl's name).
'exercises' becomes 'PT' (Physical Training).
'ada' next to 'pt' is 'ADAPT'.
(Other definitions for adapt that I've seen before include "Change to fit new circumstances" , "get used?" , "Adjust (to new condition)" , "Modify; acclimatise" , "Modify, adjust" .)