Ecologically inexperienced (5)
I believe the answer is:
green
'inexperienced' is the definition.
(similar in meaning)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for green that I've seen before include "Fresh - environmentally friendly - colour" , "Caring for environment" , "Colour of malachite" , "Unripe; environmentalist" , "Verdant; naive" .)