In new fashion, dump tie? Ill bred (10)
I believe the answer is:
multiplied
'bred' is the definition.
('multiply' can be a synonym of 'breed')
'in new fashion dump tie? ill' is the wordplay.
'in new fashion' indicates an anagram (I've seen this in other clues).
'dump'+'tie'+'ill'='dumptieill'
'dumptieill' with letters rearranged gives 'MULTIPLIED'.
(Other definitions for multiplied that I've seen before include "bred" , "grew" .)