Viperously means to behave cunningly or deceitfully, similar to a venomous snake. Synonyms for viperously include slyly, craftily, deviously, shrewdly, insidiously, dishonestly, and cunningly. These words allude to a sense of stealth and strategy, often with a sense of ill-intent. Other synonyms for viperously may include treacherously, underhandedly, deceitfully, or sneaky. Whether you are describing a person's behavior or a situation, viperously implies an air of danger and unpredictability. By choosing the right synonyms, you can expertly paint a picture of a treacherous or cunning situation, while also capturing a sense of intrigue.