Clear leader in variety show (9)
I believe the answer is:
vindicate
'clear' is the definition.
(thesaurus)
'leader in variety show' is the wordplay.
'leader in' indicates taking the first letters.
'show' becomes 'indicate' ('indicate' can be a synonym of 'show'**).
The first letter of 'variety' is 'v'.
'v'+'indicate'='VINDICATE'
(Other definitions for vindicate that I've seen before include "Avenge or exonerate" , "Divine cat (anag.)" , "Justify, clear" , "Justify by evidence or results" , "Successfully defend" .)