Love probing science with celebrity left-winger (9)
I believe the answer is:
socialist
'left-winger' is the definition.
(synonyms)
'love probing science with celebrity' is the wordplay.
'love' becomes 'o' (love means zero in tennis).
'probing' means one lot of letters goes inside another (probe can mean to poke or prod into).
'science' becomes 'sci' (eg in 'poli sci' for political science).
'with' is a charade indicator (letters next to each other).
'celebrity' becomes 'alist' (I've seen this before).
'o' put inside 'sci' is 'soci'.
'soci'+'alist'='SOCIALIST'
(Other definitions for socialist that I've seen before include "See 1" , "Political theorist" , "Fabian" , "Left-winger" , "Lefty" .)