"Chill Wills" is a colloquial phrase that refers to being relaxed, calm, and laid-back. However, if you're looking for alternative expressions to describe this state of being, there are several synonyms you can use. Serene, tranquil, and peaceful are all words that capture a sense of calmness and tranquility. Another option might be the word "easygoing", which suggests a relaxed and carefree attitude. Similarly, "mellow" conveys a state of relaxation and a lack of stress. In essence, these words can all be used as alternatives to "Chill Wills" when describing a relaxed and calm state of being.