Horny plates and pointed pins (5)
I believe the answer is:
nails
'horny plates and pointed pins' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for nails that I've seen before include "Fixing pins" , "Horny plates and pointed pins" , "Horny plates of the digits" , "Claws" , "Fixing spikes" .)