Ladies and gents beginning to exercise for free (5)
I believe the answer is:
loose
'free' is the definition.
(similar in meaning)
'ladies and gents beginning to exercise' is the wordplay.
'ladies and gents' becomes 'loos' (toilets).
'beginning to' says to take the initial letters.
The first letter of 'exercise' is 'e'.
'loos'+'e'='LOOSE'
'for' is the link.
(Other definitions for loose that I've seen before include "Unrestrained" , "Baggy" , "Not strict" , "Not fitting tightly" , "Unsecured; dissolute" .)