Slaughterously is a word that means brutally or violently, usually in the context of killing. Some synonyms for slaughterously include savagely, ferociously, viciously, ruthlessly, and mercilessly. These words describe actions that are cruel and without compassion, often resulting in a great deal of harm or destruction. Some other synonyms include ruthful, pitiless, and heartless. It is important to note that while these words may be descriptive in certain contexts, they should be used sparingly and with consideration for their impact on those who may be affected by the violence or brutality being described.