Endangers (9)
I believe the answer is:
threatens
'endangers' is the definition.
('threaten' can be a synonym of 'endanger')
This is the entire clue.
(Other definitions for threatens that I've seen before include "Puts at risk" , "Utters intentions to injure" , "Bullies" , "Imperils, jeopardises" , "Utters intention to harm" .)