Toast and greeting succeeded with Conservative (7)
I believe the answer is:
history
'toast' is the definition.
(as in you're history, you're toast)
'greeting succeeded with conservative' is the wordplay.
'greeting' becomes 'hi' (hi is a kind of greeting).
'succeeded' becomes 's' (genealogical abbreviation).
'with' says to put letters next to each other.
'conservative' becomes 'tory' (informal term for a Conservative Party member).
'hi'+'s'+'tory'='HISTORY'
'and' acts as a link.
(Other definitions for history that I've seen before include "Chronicle" , "eventful past" , "'... repeats itself'" , "Old record" , "Account of past events" .)