Cold young woman, almost glacial model (7)
I believe the answer is:
classic
'model' is the definition.
(I've seen this before)
'cold young woman almost glacial' is the wordplay.
'cold' becomes 'c' (eg on taps).
'young woman' becomes 'lass' (lass is a kind of young woman).
'almost' means to remove the last letter (most of the word but not all of it).
'glacial' becomes 'icy' ('icy' can be a synonym of 'glacial').
'icy' with its final letter removed is 'ic'.
'c'+'lass'+'ic'='CLASSIC'
(Other definitions for classic that I've seen before include "The Derby or The Oaks, for example" , "lasting literary work" , "Literary masterpiece" , "major tournament" , "Time-honoured" .)