Free former politician abducted by alien (6)
I believe the answer is:
exempt
'free' is the definition.
(exempt can mean to free or release)
'former politician abducted by alien' is the wordplay.
I cannot quite understand how this works, but
'former' could be 'ex' (prefix meaning former or onetime) and 'ex' is found in the answer.
'politician' could be 'mp' (Member of Parliament) and 'mp' is present in the answer.
'alien' could be 'et' (extraterrestrial) and 'et' is found in the leftover letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for exempt that I've seen before include "Release" , "Absolved" , "free from tax, say" , "Freed from obligation, tax etc" , "Not subject to a law" .)