Double over (4)
I'm afraid I can't explain this answer.
Can you help me to learn more?
'double over' is the definition.
(thesaurus)
This is all the clue.
(Other definitions for fold that I've seen before include "Collapse; bend in half" , "Congregation; (firm) go bankrupt" , "enclosure" , "Members of church" , "Gather < church" .)