Voluntarily avoids having worries about planet (8)
I believe the answer is:
forbears
'voluntarily avoids' is the definition.
I can't judge whether this definition defines the answer.
'worries about planet' is the wordplay.
'worries' becomes 'fears' (fearing is a kind of worrying).
'about' means one lot of letters goes inside another.
'planet' becomes 'orb' (I've seen this in another clue).
'fears' enclosing 'orb' is 'FORBEARS'.
'having' acts as a link.
Can you help me to learn more?
(Other definitions for forbears that I've seen before include "Refrains or abstains from" , "Keeps in check" , "Desists" , "doesn't!" .)