The term 'less serene' can be described as EDGIER, which is a 6 letter word. EDGIER means having a more intense or agitated quality than something that is serene. It is often used to describe a person's behavior or attitude, as well as a situation or environment. For example, a person who is edgy may be more easily angered or frustrated than someone who is serene. Similarly, an edgy environment may be more chaotic or unpredictable than a serene one.