unnerve
Unnerve is a term used to describe the act of causing someone to lose their courage, confidence, or composure. It suggests a disruption of a person's mental state, leading to feelings of unease, apprehension, or even fear. This can be achieved through various means, such as subtle actions, words, or even a person's mere presence. The effect of being unnerved is often a loss of self-assurance, making individuals more susceptible to doubt or hesitation.
Psychologically, unnerving someone can tap into their insecurities or anxieties. It can create a sense of vulnerability
In common usage, "unnerve" implies a more insidious or unsettling form of disturbance than outright fright.