The most common and most likely answer to this crossword clue is the 9 letter word ECUMENISM
E
C
U
M
E
N
I
S
M
More clues leading to the result ECUMENISM
Buddy explains!
The straight part
We know that "movement for Christian unity" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case movement for christian unity = ecumenism.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 ECUMENISM mean?
ECUMENISM noun- Ecumenical doctrines and practices, especially as manifested in the ecumenical movement.