Spike on a shoe string (4)
I believe the answer is:
lace
This clue is a double definition.
'spike' is the first definition.
(synonyms)
'shoe string' is the second definition.
(I've seen this before)
'on a' is the link.
(Other definitions for lace that I've seen before include "Fabric made in openwork design" , "Delicate fabric woven in an open web" , "Spike - ornamental fabric" , "Delicate material" , "Flimsy fabric or shoe fasterner" .)