There are several synonyms for the word "blamefully" that can be used to convey a sense of culpability or guilt. Some possible options include "culpably," "guiltily," "responsibly," "accountably," "remorsefully," and "shamefacedly." Each of these words can help to emphasize the idea of wrongdoing or impropriety, whether in reference to a specific action or a general sense of ethical or moral violation. By using these synonyms, writers can add nuance and complexity to their language, highlighting the shades of meaning that exist within the word "blamefully" and creating a more vivid and engaging narrative for their readers.