relating to or resembling a viper, often used to describe something that is treacherous or dangerous.

नागिन जैसा

English Usage: Her viperine instincts made it hard for her to trust anyone.

Hindi Usage: उसकी नागिन जैसी प्रवृत्तियाँ किसी पर विश्वास करना कठिन बना देती थीं।