Cloak left out of travelling bag (7)
I believe the answer is:
manteau
'cloak' is the definition.
(I've seen this before)
'left out of travelling bag' is the wordplay.
'left' becomes 'port' (left side of a ship - opposite of starboard).
'out of' is a deletion indicator ('out of' can mean no longer having).
'travelling bag' becomes 'portmanteau' (I've seen this before).
'portmanteau' with 'port' taken away is 'MANTEAU'.
(Other definitions for manteau that I've seen before include "cloak" , "Lady's loose gown" .)