Large travelling bag (11)
'large travelling bag' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for portmanteau that I've seen before include "Large travelling bag that opens flat" , "Word such as "bromance"" , "Brunch this term" , "Large old case" , "said to have several uses" .)
(Other definitions for holdall that I've seen before include "retainer" , "Large strong bag with handles or shoulder strap" , "A large soft travelling bag - stuff everything in" , "Capacious bag or basket" , "Large bag (no need for another?)" .)