Yankee great Mickey (6)
I believe the answer is:
mantle
'yankee great mickey' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for mantle that I've seen before include "Loose outer garment or covering" , "Layer below earth's crust" , "Lament in loose cloak" , "A cloak, cover" , "Cloak or loose outer garment" .)