One to disallow large headline? (6)
I believe the answer is:
banner
I believe this is a double definition.
'one to disallow' is the first definition.
(someone disallowing or banning things)
'large headline?' is the second definition.
(banner headline is a type of newspaper headline)
(Other definitions for banner that I've seen before include "Pennant" , "Standard; heading" , "Angry scientist" , "Streamer, flag" , "Website advert; flag" .)