There are several synonyms for the phrase "clump together," including cluster, gather, bunch up, huddle, and group. These terms typically describe the act of objects, animals, or people coming together in a tight, compact manner. Clustering, for example, refers to a group of objects that are close together, while gathering suggests the coming together of people or things for a specific purpose or event. "Bunch up" is often used to describe clothing or objects that have become entangled or compressed, while "huddle" usually refers to people getting close together in order to stay warm or to discuss something. Finally, "group" is a broad term that can refer to any collection of people, animals, or things.