Naughtily seduce about a hundred? Get on! (7)
I believe the answer is:
succeed
'get on' is the definition.
(thesaurus)
'naughtily seduce about a hundred?' is the wordplay.
'naughtily' indicates anagramming the letters.
'about' indicates putting letters inside.
'a hundred?' becomes 'c' (Roman numeral).
'seduce' with letters rearranged gives 'suceed'.
'suceed' enclosing 'c' is 'SUCCEED'.
(Other definitions for succeed that I've seen before include "Take the place previously occupied by - be a winner" , "Follow on - win" , "Achieve one's ambitions" , "Reach one's goal" , "Take over a title from (someone)" .)