Loyal cadet died fighting (9)
I believe the answer is:
dedicated
'loyal' is the definition.
(similar in meaning)
'cadet died fighting' is the wordplay.
'fighting' indicates anagramming the letters (I've seen this in other clues).
'cadet'+'died'='cadetdied'
'cadetdied' is an anagram of 'DEDICATED'.
(Other definitions for dedicated that I've seen before include "Diligent" , "Committed" , "exclusive" , "Devoted to a particular cause or purpose" , "Hard working" .)