Trousers needing inch off, so sent back (6)
I believe the answer is:
chinos
'trousers' is the definition.
(chinos are a type of trousers)
'inch off so sent back' is the wordplay.
'off' indicates anagramming the letters.
'sent back' says the letters should be written backwards.
'so' back-to-front is 'os'.
'inch' anagrammed gives 'chin'.
'chin'+'os'='CHINOS'
'needing' is the link.
(Other definitions for chinos that I've seen before include "Casual cotton trousers" , "Trousers made from a twilled cotton" .)