Send off old wine (6)
I believe the answer is:
export
'send off' is the definition.
(thesaurus)
'old wine' is the wordplay.
'old' becomes 'ex' (prefix meaning former or onetime).
'wine' becomes 'port' (port is a kind of wine).
'ex'+'port'='EXPORT'
(Other definitions for export that I've seen before include "strong brown beer" , "Carry out of country" , "Sell goods abroad" , "Send goods for sale abroad" , "Dispose of to another country" .)