Newsflash: weight added to burden (4,5)
I believe the answer is:
stop press
'newsflash weight' is the definition.
The definition suggests a singular noun which matches the answer.
'added to burden' is the wordplay.
'added to' becomes 'st' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'burden' becomes 'oppress' (I've seen this in another clue).
'st'+'oppress'='STOP-PRESS'
Can you help me to learn more?
(Other definitions for stop press that I've seen before include "breaking intelligence" , "Late breaking news" , "Hold the front page!" , "newspaper feature" , "Latest news" .)