To come together is right and proper (4)
I believe the answer is:
meet
This clue is a triple definition!
'to come together' is the first definition.
(to meet is to gather or come together)
'is right' is the second definition.
(thesaurus)
'and' acts as a link.
'proper' is the third definition.
(I've seen this in another clue)
(Other definitions for meet that I've seen before include "Satisfy (requirements)" , "Bump into" , "counter" , "Come together or run into" , "Fitting to come together" .)