The phrase "in a stew" refers to being in a state of worry, anxiety, or confusion. Antonyms for this phrase include "at ease," "calm," "composed," "cool," "serene," and "unperturbed." When someone is "at ease," they are relaxed and comfortable, free from anxiety or tension. "Calm" refers to a state of tranquility or peacefulness, while "composed" means to be in a state of self-possession or composure. "Cool" suggests a lack of intensity or emotional agitation. "Serene" describes a sense of peacefulness, and "unperturbed" suggests a state of mental calmness, steadiness, and resilience.