Grizzled (5)
I believe the answer is:
hoary
'grizzled' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for hoary that I've seen before include "Grey-haired and old" , "Grey haired; old (joke)" , "Grizzly - ancient" , "White or grey, or old as of joke" , "Grizzled or frosted" .)