Take off a penny in change (8)
I believe the answer is:
amputate
'take off' is the definition.
'a penny in change' is the wordplay.
'penny' becomes 'p'.
'in' means one lot of letters goes inside another.
'change' becomes 'mutate' (mutating is a kind of changing**).
'p' placed within 'mutate' is 'mputate'.
'a'+'mputate'='AMPUTATE'
(Other definitions for amputate that I've seen before include "Cut off an arm or a leg" , "Surgically remove all or part of limb" , "In theatre, remove" , "Cut off (a limb)" , "Sever" .)