Churned up is a phrase that refers to a state of emotional turmoil, confusion or agitation. The antonym of churned up is calm or serene. When someone is calm or serene, they are composed, tranquil and peaceful. They can be described as relaxed or unruffled. The calmness can be a result of the environment or situations, or it can be an individual's personality trait. A serene individual is known to have a better mental state, improved physical health, and a more productive lifestyle. When someone is tranquil, they are not easily agitated, and they are better equipped to deal with challenging situations that come their way.