The crossword solution for the term 'ONE CALLING FOUL?' is 'SWEARER' with 7 letters. The term 'SWEARING' is used to describe the act of using profane or offensive language, usually in a loud and aggressive manner. It is often used as a form of protest or to express strong emotions. In the context of the phrase 'one calling foul?', it could refer to someone who is protesting an unfair situation or decision.