Cut broadcaster admits is inadequate (7)
I believe the answer is:
sketchy
'inadequate' is the definition.
(thesaurus)
'cut broadcaster admits' is the wordplay.
'cut' becomes 'etch' (I've seen this before).
'broadcaster' becomes 'sky' (Sky is a television company).
'admits' is an insertion indicator.
'etch' placed into 'sky' is 'SKETCHY'.
'is' acts as a link.
(Other definitions for sketchy that I've seen before include "Incomplete; rough" , "Imperfect" , "lacking detail" , "Imprecise" , "Not thorough or detailed" .)