Reportedly remained sedate (5)
I believe the answer is:
staid
'sedate' is the definition.
('staid' can be a synonym of 'sedate')
'reportedly remained' is the wordplay.
'reportedly' indicates a 'sounds like' (homophone) clue.
'remained' becomes 'stayed' (staying is a kind of remaining).
'stayed' is a homophone of 'STAID'.
(Other definitions for staid that I've seen before include "composed" , "Unadventurous, dull" , "Serious or sober in character" , "Sober, grave" , "Settled" .)