Mother gets clean away in handcuff (7)
I believe the answer is:
manacle
'handcuff' is the definition.
(I know that handcuff can be written as manacle)
'mother gets clean away' is the wordplay.
'mother' becomes 'ma' (ma can mean mother).
'gets' means one lot of letters goes inside another.
'away' indicates an anagram (letters move away from their original places).
'clean' anagrammed gives 'nacle'.
'ma' going within 'nacle' is 'MANACLE'.
'in' acts as a link.
(Other definitions for manacle that I've seen before include "Hand/ankle restraint" , "Shackle on the wrist" , "restricting at the cuff?" , "item restricting movement" , "Handcuff" .)