Handcuff chap, adult, oddly calmed (7)
I believe the answer is:
manacle
'handcuff' is the definition.
('manacle' can be a synonym of 'handcuff')
'chap adult oddly calmed' is the wordplay.
'chap' becomes 'man' (I've seen this before).
'adult' becomes 'a'.
'oddly' indicates alternate letters.
The alternate letters of 'calmed' are 'cle'.
'man'+'a'+'cle'='MANACLE'
(Other definitions for manacle that I've seen before include "item restricting movement" , "Shackle on the wrist" , "Hand/ankle restraint" , "Metal shackle" , "restricting at the cuff?" .)