Fuel cut, briefly (3)
I believe the answer is:
gas
'fuel' is the definition.
(gas is a fuel)
'cut briefly' is the wordplay.
'cut' becomes 'gash' (a gash is a wound or cut).
'briefly' means to remove the last letter.
'gash' with its final letter taken off is 'GAS'.
(Other definitions for gas that I've seen before include "Talk profusely" , "Fumes, vapour" , "Fuel; idle talk" , "Chat (colloq.)" , "Domestic fuel" .)