Sang-froid is a French term that refers to composure and self-possession in difficult or stressful situations. It is often used to describe a person who manages to remain calm under pressure. Antonyms of sang-froid include words such as panic, hysteria, agitation, and anxiety. These terms describe the opposite phenomenon of losing control in stressful situations. Other antonyms of sang-froid would be synonyms to extreme emotions such as anger, fear, and despair. It is important to note that while the concept of sang-froid implies a certain level of emotional control, it is also associated with resilience, perseverance, and adaptability.