See UN Assembly follow (5)
I believe the answer is:
ensue
'follow' is the definition.
(ensue can mean to follow or happen as a result)
'see un assembly' is the wordplay.
'assembly' indicates anagramming the letters.
'see'+'un'='seeun'
'seeun' anagrammed gives 'ENSUE'.
(Other definitions for ensue that I've seen before include "Transpire" , "Come along afterwards" , "Follow subsequently" , "Happen as consequence or afterward" , "Occur as a result (of)" .)