More dismissive of broadcast that's finally over (6)
I believe the answer is:
airier
'more dismissive' is the definition.
(I've seen this before)
'broadcast that's finally over' is the wordplay.
'broadcast' becomes 'air' ('air' can be a synonym of 'broadcast'**).
'that's' becomes 'ie'.
'finally' indicates one should take the final letters.
The last letter of 'over' is 'r'.
'air'+'ie'+'r'='AIRIER'
'of' acts as a link.
(Other definitions for airier that I've seen before include "More dismissive" , "Breezier" , "More spacious and better ventilated" .)