To scare a person or an animal away from a particular place or thing. A noun or pronoun can be used between "frighten" and "off." Can you guys quit screaming at each other in the middle of the department? You're going to frighten off my 2 o'clock interview! I can do basic car repairs, but a major one like that would frighten me off, honestly. He shot his rifle in the air to frighten off the wolves.