Scholarly cadet due for training (8)
I believe the answer is:
educated
'scholarly' is the definition.
(thesaurus)
'cadet due for training' is the wordplay.
'for training' indicates anagramming the letters ('train' can mean to shape the growth of a plant).
'cadet'+'due'='cadetdue'
'cadetdue' is an anagram of 'EDUCATED'.
(Other definitions for educated that I've seen before include "Clever" , "Well-read" , "Trained; learned" , "Cultivated, knowledgeable" , "Civilised" .)