Don't leave religious group for what looks like just another branch (5,6)
I believe the answer is:
stick insect
'don't leave religious group for what looks like' is the definition.
I can't tell whether this definition defines the answer.
'another branch' is the wordplay.
'another' becomes 'stickin' (I can't justify this - if you can you should believe this answer much more).
'branch' becomes 'sect' (I've seen this in another clue).
'stickin'+'sect'='STICK-INSECT'
'just' acts as a link.
Can you help me to learn more?
(Other definitions for stick insect that I've seen before include "Twiggy type" , "It resembles a twig" , "One well-camouflaged" , "creature hard to spot in tree" , "Its body has virtually no substance" .)