Refresh a Frenchman with whiskey (5)
I believe the answer is:
renew
'refresh' is the definition.
(thesaurus)
'a frenchman with whiskey' is the wordplay.
'a frenchman' becomes 'rene'.
'with' is a charade indicator (letters next to each other).
'whiskey' becomes 'w' (alpha bravo charlie delta ...).
'rene'+'w'='RENEW'
(Other definitions for renew that I've seen before include "Restore - recommence" , "modernise" , "Restore to original state" , "Extend loan period" , "Extend eg library loan" .)