Recluse in leather mittens (6)
I believe the answer is:
hermit
'recluse' is the definition.
('hermit' can be a synonym of 'recluse')
'in leather mittens' is the wordplay.
'in' indicates the answer is hidden within the clue.
'HERMIT' is hidden within 'leather mittens'.
(Other definitions for hermit that I've seen before include "Solitary dweller" , "One lives an isolated religious life" , "Ascetic who leads an isolated life" , "Person like Peter" , "One who lives in solitude, like kind of crab" .)