Happened (8)
'happened' is the definition.
('occur' can be a synonym of 'happen')
This is the entire clue.
(Other definitions for occurred that I've seen before include "Took place" , "Happened" , "Came to pass" .)
'happened' is the definition.
('befall' can be a synonym of 'happen')
This is all the clue.
(Other definitions for befallen that I've seen before include "Came to pass" , "(Having) happened to (someone)" .)