Captain (6)
'captain' is the definition.
(thesaurus)
This is all the clue.
(Other definitions for leader that I've seen before include "Principal player in an orchestra" , "Opinion piece; boss" , "Front-runner or head of group" , "Chief or front man" , "One in command" .)
'captain' is the definition.
(I know that skipper is a type of captain)
This is the entire clue.
(Other definitions for skipper that I've seen before include "Ship's captain (colloq.)" , "one that's put over the side" , "Chap aboard trawler" , "sleep in outhouse" , "girl with rope?" .)