Dissuades (6)
I believe the answer is:
deters
'dissuades' is the definition.
('deter' can be a synonym of 'dissuade')
This is all the clue.
(Other definitions for deters that I've seen before include "Persuades or discourages from doing" , "Puts off" , "Discourages, dissuades" , "Discourages or hinders" , "Discourages or prevents from doing something" .)