Fools broadcast, getting medium rating (10)
I believe the answer is:
assessment
'rating' is the definition.
(I've seen this in another clue)
'fools broadcast getting medium' is the wordplay.
'fools' becomes 'asses' (ass can mean a foolish person).
'broadcast' becomes 'sent' (sent or transmitted as a broadcast).
'getting' is an insertion indicator.
'medium' becomes 'm' (as in UK clothing sizes).
'sent' placed around 'm' is 'sment'.
'asses'+'sment'='ASSESSMENT'
(Other definitions for assessment that I've seen before include "Judgement" , "Process of valuation" , "Survey" , "Evaluation, estimation" , "rating" .)