Being hirsute is dangerous! (5)
I believe the answer is:
hairy
I believe this is a double definition.
'being hirsute' is the first definition.
('hairy' can be a synonym of 'hirsute')
'dangerous' is the second definition.
(I've seen this before)
'is' is the link.
(Other definitions for hairy that I've seen before include "alarming" , "Scary" , "description of Jacob's brother Esau" , "like Esau" , "Frightening - like a bear?" .)