I'm not a lawyer but have been responsible for many employees. This is my understanding of the legal definition of a hostile work environment:
"Some employees believe that a bad boss, an unpleasant work environment, a rude coworker, failure to qualify for a promotion, or the lack of perks, privileges, benefits, and recognition can create a hostile work environment. But, the reality is that for a workplace to be hostile, certain legal criteria must be met.
A hostile work environment is created by a boss or coworker whose actions, communication or behavior make doing your job impossible.
This means that the behavior altered the terms, conditions, and/or reasonable expectations of a comfortable work environment for employees.
Additionally, the behavior, actions or communication must be discriminatory in nature. Discrimination is monitored and guided by the Equal Employment Opportunity Commission (EEOC) which was created by the Civil Rights Act of 1964."