Proper contest ended early (3)
I believe the answer is:
due
'proper' is the definition.
(I've seen this before)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for due that I've seen before include "Deserved or unpaid" , "Expected; appropriate" , "Owed, or payable immediately" , "Expected; proper" , "Expected, scheduled" .)