Origin of daily newspaper is a dull affair (4)
I believe the answer is:
drag
'a dull affair' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'origin of daily newspaper' is the wordplay.
'origin of' indicates taking the first letters.
'newspaper' becomes 'rag' (informal term for a newspaper).
The first letter of 'daily' is 'd'.
'd'+'rag'='DRAG'
'is' acts as a link.
Can you help me to learn more?
(Other definitions for drag that I've seen before include "woman's attire" , "Trail; bore" , "A bore (colloq.); lug" , "Haul - queen's garb?" , "Bind" .)