Ceased giving deductions in a new fashion (12)
I believe the answer is:
discontinued
'ceased' is the definition.
('discontinue' can be a synonym of 'cease')
'giving deductions in a new fashion' is the wordplay.
'giving' means one lot of letters go next to another.
'a new fashion' indicates anagramming the letters.
'deductions' next to 'in' is 'deductionsin'.
'deductionsin' with letters rearranged gives 'DISCONTINUED'.
(Other definitions for discontinued that I've seen before include "Stopped" , "No longer produced" .)