Mob will stockpile, we hear (5)
I believe the answer is:
horde
'mob will' is the definition.
'horde' can be an answer for 'mob' (horde can mean a mob or crowd of people). I'm not sure about the 'will' bit.
'stockpile we hear' is the wordplay.
'stockpile' becomes 'hoard' (I've seen this in another clue).
'we hear' shows a homophone (sound like).
'hoard' sounds like 'HORDE'.
Can you help me to learn more?
(Other definitions for horde that I've seen before include "A swarm or multitude" , "Many people" , "Nomadic army" , "lots of people" , "Large force" .)