Stickler died in training soldier (6)
I believe the answer is:
pedant
'stickler' is the definition.
(I've seen this before)
'died in training soldier' is the wordplay.
'died' becomes 'd' (abbreviation next to the year of someone's death).
'in' is an insertion indicator.
'training' becomes 'PE' (Physical Education).
'soldier' becomes 'ant' (soldier is a type of ant).
'pe'+'ant'='peant'
'd' inserted into 'peant' is 'PEDANT'.
(Other definitions for pedant that I've seen before include "Bookish egghead" , "Stickler for the rules" , "Particular type" , "Panted like stickler for accuracy" , "A sticklet for formal rules and details" .)