Short suit in item of luggage (9)
I believe the answer is:
briefcase
'item of luggage' is the definition.
'briefcase' can be an answer for 'luggage' (thesaurus). I'm unsure of the 'item of' bit.
'short suit' is the wordplay.
'short' becomes 'brief' (synonyms).
'suit' becomes 'case' (synonyms).
'brief'+'case'='BRIEFCASE'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for briefcase that I've seen before include "See fabric covering container for business papers" , "Carried by lawyer" , "Portable receptacle for documents" , "providing security for the papers" , "Container for carrying papers" .)