Influential males in management (7)
I believe the answer is:
seminal
'influential' is the definition.
(thesaurus)
'males in management' is the wordplay.
'management' is an anagram indicator.
'males'+'in'='malesin'
'malesin' is an anagram of 'SEMINAL'.
(Other definitions for seminal that I've seen before include "Very important, original" , "Menials giving rise to new beginnings" , "Major" , "Strongly influential" , "Majorly influential" .)