Synthetic rubber (8)
I believe the answer is:
neoprene
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">synthetic rubber</span>' is the definition.<br/ ><span class="explanation-format__explanation">(neoprene is a kind of synthetic rubber)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for neoprene that I've seen before include "Synthetic like rubber" , "Synthetic rubber-like polymer" , "Synthetic polymer; none peer (anag.)" , "Synthetic rubber - ne'er open (anag)" .)