Identical, bespoke-quality trousers (5)
I believe the answer is:
equal
'identical' is the definition.
(thesaurus)
'bespoke-quality trousers' is the wordplay.
'trousers' indicates a hidden word (to trouser can mean to contain or hold).
'EQUAL' can be found hidden inside 'bespoke quality'.
(Other definitions for equal that I've seen before include "The same; even" , "Equivalent or equitable" , "Peer; rival" , "Evenly-matched" , "The same in quantity, status etc" .)