Restraint needed during calls for locks (8)
I believe the answer is:
ringlets
'for locks' is the definition.
('ringlet' can be a synonym of 'lock')
'restraint needed during calls' is the wordplay.
'restraint' becomes 'let' (let can mean a restraint or obstacle).
'needed during' indicates putting letters inside.
'calls' becomes 'rings' ('ring' can be a synonym of 'call').
'let' inserted within 'rings' is 'RINGLETS'.
(Other definitions for ringlets that I've seen before include "Spiral curls" , "Curls or tendrils" , "Sterling sort of curls" , "Locks" , "Curls, of Irish dancers say" .)