viper
n. countable C2 Proficiency US //ˈvaɪpɝ// UK //vˈaɪpɐ// viper
n. a type of poisonous snake with long teeth. You can also use this word to describe a person who is mean or tries to hurt others secretly.
n. a venomous snake belonging to the family Viperidae, characterised by long, hinged fangs. Figuratively describes a person perceived as treacherous, malicious, or spiteful.
The hiker saw a viper hiding in the tall grass.
He warned his colleagues that the new manager was a viper who would betray them to get a promotion.
The protagonist soon realised that the court was filled with vipers, each waiting for a moment of weakness to strike at his reputation.
Usage
When used figuratively for a person, it carries a strong negative connotation of betrayal.