Makes fast tresses (5)
I believe the answer is:
locks
This clue is a double definition.
'makes fast' is the first definition.
(locking is a kind of making fast)
'tresses' is the second definition.
(I've seen this in another clue)
(Other definitions for locks that I've seen before include "Secures; person's hair" , "Secure fasteners for doors" , "Securely fixes" , "Tresses" , "raising devices for sailors" .)