Rite using flag (4)
I believe the answer is:
tire
'flag' is the definition.
(both can mean to become weary)
'rite using' is the wordplay.
'using' indicates an anagram (the letters used in a different way).
'rite' with letters rearranged gives 'TIRE'.
(Other definitions for tire that I've seen before include "Grow weary of rite" , "Feel in need of rest" , "Fatigue" , "Become weary" , "one of four found on Chevrolet?" .)