The most common and most likely answer to this crossword clue is the 8 letter word ANTIPOPE
I've seen this crossword clue in Financial Times
A
N
T
I
P
O
P
E
More clues leading to the result ANTIPOPE
- Rebel church leader disliking work among vacuous people
- Dad in a new relationship, a man challenging religious authority
- Unorthodox head’s key refusal to accept point
- Appoint new European leader based in Avignon, perhaps
- A refusal to accept advice in rival religious authority
- Appoint new leader of ecclesia? This one’s not approved
- A refusal to admit hint for religious leader’s rival
- The Bishop of Rome in opposition to one canonically chosen almost appointed strangely
Buddy explains!
The straight part
We know that "leader based in Avignon, perhaps" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case leader based in avignon, perhaps = antipope.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ANTIPOPE mean?
ANTIPOPE noun- A person who claims or claimed to be the pope, usually as the result of a disputed election or deposition, but is not considered by the Roman Catholic Church to be the real pope.