God, European is taking on vacuous zealots (4)
I believe the answer is:
zeus
'god' is the definition.
(Zeus is an example)
'european is taking on vacuous zealots' is the wordplay.
'european' becomes 'E' (abbreviation e.g. EU).
'is taking' becomes 'u' (I can't justify this - if you can you should believe this answer much more).
'on' means one lot of letters goes inside another.
'vacuous' suggests removing the centre.
'zealots' with its middle removed is 'zs'.
'e'+'u'='eu'
'eu' placed inside 'zs' is 'ZEUS'.
Can you help me to learn more?
(Other definitions for zeus that I've seen before include "Greek god - husband and brother of Hera" , "old Greek" , "Divine son of Cronos and Rhea" , "Chief Olympian deity" , "Ancient Greece's top god" .)