Warrior spirit reflected in development of Asia (7)
I believe the answer is:
samurai
'warrior' is the definition.
(samurai is a kind of warrior)
'spirit reflected in development of asia' is the wordplay.
'spirit' becomes 'rum' (I've seen this before).
'reflected' shows that the letters should be reversed in order.
'in' means one lot of letters goes inside another.
'development of' indicates an anagram (I've seen 'development' mean this).
'rum' backwards is 'mur'.
'asia' is an anagram of 'saai'.
'mur' going into 'saai' is 'SAMURAI'.
(Other definitions for samurai that I've seen before include "Feudal Japanese warrior" , "Traditional warriors of Japan" , "Sudoku variant" , "military man" , "Japanese fighter" .)