viper

noun4

1. •
   A venomous snake in the family Viperidae.
2. •
   (informal) Any venomous snake.
3. •
   (figurative) A dangerous, treacherous, or malignant person.

   • And aggravate my folly who committed / To such a viper his most sacred trust / Of secresie, my safety, and my life. — 1671
4. •
   (slang) A person who smokes marijuana.

   • Dreamed about a reefer five feet long / Mighty Mezz, but not too strong / You'll be high but not for long / If you're a viper — 1936