Expected; proper (3)
I believe the answer is:
due
I believe this clue is a double definition.
'expected' is the first definition.
(similar in meaning)
'proper' is the second definition.
(what is due is what is proper or appropriate)
(Other definitions for due that I've seen before include "Expected; proper" , "Escort" , "Proper, appropriate" , "Proper; owed" , "Entitlement" .)