Spearhead stolen from tyrant's warehouse (5)
I believe the answer is:
depot
'warehouse' is the definition.
(I know that depot is a type of warehouse)
'spearhead stolen from tyrant's' is the wordplay.
'spearhead' becomes 's' (head letter of 'spear').
'stolen from' suggests deleting specific letters.
'tyrant' becomes 'despot' (synonyms).
'despot' with 's' removed is 'DEPOT'.
(Other definitions for depot that I've seen before include "Place where buses and trains are kept" , "storeroom" , "Regimental HQ" , "Storage base" , "Large storage site" .)