The phrase "all by lonesome" is an informal expression used to describe someone who is alone or isolated. There are several synonyms for this phrase, including "all alone," "all by oneself," "solitary," and "lonely." Each of these terms conveys a slightly different nuance, but all describe a state of being alone. "All alone" and "all by oneself" suggest a self-sufficient state of being alone, while "solitary" implies a preference for being alone. "Lonely," on the other hand, has a negative connotation, suggesting a feeling of sadness or isolation. Regardless of the term used, being alone can be a difficult state, but it can also provide opportunity for introspection and self-discovery.