Reportedly produced a low morose feeling (4)
I believe the answer is:
mood
'morose feeling' is the definition.
(I know that mood is a type of morose feeling)
'reportedly produced a low' is the wordplay.
'reportedly' shows a homophone (sound like).
'produced a low' becomes 'mooed' (low can mean a mooing sound).
'mooed' is a homophone of 'MOOD'.
(Other definitions for mood that I've seen before include "State of mind or emotion" , "Depression" , "at times appears very high" , "Feeling of doom" , "State of mind, humour" .)