Contain everything in grip (7)
I believe the answer is:
holdall
'grip' is the definition.
(thesaurus)
'contain everything' is the wordplay.
'contain' becomes 'hold' ('hold' can be a synonym of 'contain').
'everything' becomes 'all' (I've seen this before).
'hold'+'all'='HOLDALL'
'in' acts as a link.
(Other definitions for holdall that I've seen before include "Large bag (no need for another?)" , "Large case, with handles" , "Big bag" , "A large soft travelling bag - stuff everything in" , "Largish bag" .)