More eco-friendly (7)
I believe the answer is:
greener
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">more eco-friendly</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for greener that I've seen before include "The grass is always thus on the other side of the hill" , "more concerned about the environment" , "more colourful" , "better for the environment" , "More gullible" .)