It cuts both ways (3-5,5)
I believe the answer is:
two-edged sword
'it cuts both ways' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for two-edged sword that I've seen before include "One cutting both ways" , "We get odd words (anag) - it cuts both ways" , "Something offering both good and bad outcomes" .)