Cageling is a term that refers to a bird or animal that is kept in a cage. However, there are several synonyms that can be used to describe this same concept. One option is to use the word "captive," which refers to any animal that is held against its will. Another synonym is "prisoner," which can be used to describe not only animals, but also humans who are confined to a small space. Additionally, the term "confined" can be used to describe any animal or person that is restricted to a small area. Other synonyms include "encaged," "cooped up," "caged," and "imprisoned." Each of these words can be used to describe the same basic concept of animals or humans being kept in a confined space.