Influential man lies disgracefully (7)
I believe the answer is:
seminal
'influential' is the definition.
(thesaurus)
'man lies disgracefully' is the wordplay.
'disgracefully' indicates an anagram.
'man'+'lies'='manlies'
'manlies' is an anagram of 'SEMINAL'.
(Other definitions for seminal that I've seen before include "Groundbreaking" , "Generating new developments for menials" , "Menials giving rise to new beginnings" , "Very important, original" , "Of seed, or giving rise to new developments" .)