Outstanding kind of key officer (5)
I believe the answer is:
major
I believe this clue is a quadruple definition!!
'outstanding' is the first definition.
(similar in meaning)
'kind' is the second definition.
Both the answer and definition are adjectives. Perhaps they are linked in a way I don't understand?
'of' is a link.
'key' is the third definition.
(thesaurus)
'officer' is the fourth definition.
(type of military officer)
Can you help me to learn more?
(Other definitions for major that I've seen before include "See 2" , "5,27 [PRIME MINISTER]" , "Army officer immediately junior to a lieutenant colonel" , "See 11 Across" , "Military rank" .)