Ruminative lyrics are those that delve into introspective and contemplative themes. Synonyms for this kind of music could include reflective, meditative, pensive or introspective. These words convey a sense of contemplation and deep thought, such as when an artist is reflecting on their past experiences or musing on their emotions. Other similar words that could be used to describe this sort of music might include ruminant, ruminating, or brooding. Essentially, these words all describe music that is focused on introspection and contemplation and are often used to describe works by singer-songwriters or other musicians who delve deeply into their own thoughts and emotions.