Long to suppress most of restraint? That'll be nice (8)
I believe the answer is:
pleasant
'nice' is the definition.
(associated in meaning)
'long to suppress most of restraint?' is the wordplay.
'long' becomes 'pant' (I've seen this before).
'to suppress' is an insertion indicator.
'most of restraint?' becomes 'leas' (I am not sure about this - if you are sure you should believe this answer much more).
'pant' enclosing 'leas' is 'PLEASANT'.
'that'll be' acts as a link.
Can you help me to learn more?
(Other definitions for pleasant that I've seen before include "Affable, good-humoured" , "Delightful" , "Enjoyable, nice" , "Charming" , "Enjoyable, agreeable" .)