English company head is keen environmentalist (6)

I believe the answer is:

econut

I'm a little stuck... Click here to teach me more about this clue!

'keen environmentalist' is the definition.
I know nothing about this answer so I can't judge whether this works.

'english company head' is the wordplay.
'english' becomes 'E' (abbreviation as in OED).
'company' becomes 'co' (abbreviation).
'head' becomes 'nut' (informal term for somebody's head).
'e'+'co'+'nut'='ECONUT'

'is' acts as a link.

Can you help me to learn more?

(Another definition for econut that I've seen is " green activist".)

I've seen this clue in The Independent.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.