More eco-friendly (7)
I believe the answer is:
greener
'more eco-friendly' is the definition.
(I've seen this before)
This is the entire clue.
(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" .)