Synthetic fibre; paint (7)
I believe the answer is:
acrylic
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">synthetic fibre</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">paint</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(acrylic paint is a kind of paint)</span><br/ ><br/ ></span>
(Other definitions for acrylic that I've seen before include "fibre that's synthetic" , "Synthetic fibre or paint" , "The synthetic fibre is icy, Carl" , "Synthetic resin or fibre used for textiles" , "Kind of paint" .)