Verb (5-dan, す, transitive)
1. to intimidate; to frighten; to scare
クマの出没が住民を脅かしている。Bear sightings are frightening the local residents.
2. to threaten (e.g. peace); to jeopardize; to endanger; to imperil
だがその炎が選手たちの命を脅かすことはなかった。However, that flame did not endanger the lives of the players.