Said to touch on clasp (6)
I believe the answer is:
brooch
'clasp' is the definition.
(I know that clasp can be written as brooch)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for brooch that I've seen before include "Jewellery item with pin" , "Adornment for dress" , "Breastpin" , "Ornament with a hinged pin and catch" , "Decorative pin" .)