Red, say (6)
I believe the answer is:
colour
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">red say</span>' is the definition.<br/ ><span class="explanation-format__explanation">(red is a kind of colour)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for colour that I've seen before include "Complexion - pretext" , "Hue, shade" , "black?" , "Pigment, paint or dye" , "Influence" .)