Material from most unsuitable news boss? (7)
I believe the answer is:
worsted
'material' is the definition.
(worsted is a kind of material)
'most unsuitable news boss?' is the wordplay.
'most unsuitable' becomes 'worst' (similar in meaning).
'news boss?' becomes 'ed' (short for editor).
'worst'+'ed'='WORSTED'
'from' acts as a link.
(Other definitions for worsted that I've seen before include "material" , "Set word (anag.)" , "stuff" , "Beaten" , "Beat" .)