Fuel price doubled initially (4)
I believe the answer is:
feed
'fuel' is the definition.
(thesaurus)
'price doubled initially' is the wordplay.
'price' becomes 'fee' (I've seen this in other clues).
'initially' suggests taking the first letters.
The initial letter of 'doubled' is 'd'.
'fee'+'d'='FEED'
(Other definitions for feed that I've seen before include "Nourish" , "Provide food" , "take courses" , "comedian's assistant" , "Provide something to eat" .)