Pack squirrel away that's been caught? (5)
I believe the answer is:
horde
'pack' is the definition.
(thesaurus)
'squirrel away that's been caught?' is the wordplay.
'squirrel away' becomes 'hoard' (synonyms).
'that's been caught?' indicates a 'sounds like' (homophone) clue (I've seen 'is caught' mean this).
'hoard' sounds like 'HORDE'.
(Other definitions for horde that I've seen before include "Vast multitude" , "A mob of people" , "Large force" , "Nomadic army" , "Large group of people" .)