"Reasonable apprehension" is a term that means feeling worried or fearful about something, but it is based on logical and understandable reasons. It is a realistic or sensible sense of concern or anxiety. Full definition
A finding of reasonable apprehension of bias in these circumstances may make it more difficult for future arbitrator - practitioners in specialized areas. (slaw.ca)
Physical threat means conduct that places a person in reasonable apprehension of imminent, serious physical harm and includes any attempt or actual infliction of physical harm. (ecode360.com)
An act by the perpetrator that creates reasonable apprehension of harm by the victim (someone coming at you with a baseball bat). (1law.com)