Flesh mostly to freeze in tight corset (6)
I believe the answer is:
bodice
'tight corset' is the definition.
'flesh mostly to freeze' is the wordplay.
'flesh' becomes 'body'.
'mostly' means to remove the last letter.
'to freeze' becomes 'ice' (I've seen this before).
'body' with its final letter taken away is 'bod'.
'bod'+'ice'='BODICE'
'in' is the link.
(Other definitions for bodice that I've seen before include "Old undergarment is visible" , "Historical novel with lots of passion" , "Top of a dress above the waist" , "Sexually explicit historical novel" , "tight-fitting costume?" .)