Lively do with brandy to start, then port (3,4)
I believe the answer is:
con brio
'lively' is the definition.
(musical term)
'do with brandy to start then port' is the wordplay.
'do' becomes 'con' (both can mean to defraud).
'with' says to put letters next to each other.
'to start' indicates taking the first letters.
'then' is a charade indicator (letters next to each other).
'port' becomes 'rio' (Rio de Janeiro is a port).
The first letter of 'brandy' is 'b'.
'con'+'b'+'rio'='CON BRIO'
(Other definitions for con brio that I've seen before include "Lively, musically speaking" , "Musically, with spirit" , "Energetically" , "(In music) with vigour" , "In music, with spirit and verve" .)