French king giving us oil (5)
I believe the answer is:
louis
'french king' is the definition.
(I've seen this before)
'giving us oil' is the wordplay.
'giving' indicates an anagram (the letters give the letters for another word).
'us'+'oil'='usoil'
'usoil' is an anagram of 'LOUIS'.
(Other definitions for louis that I've seen before include "and 23: US jazz trumpeter" , "French gold coin" , "Joe ---, the Brown Bomber" , "-- Armstrong, trumpeter" , "Many kings of France" .)