cottonmouth

noun

• 1a large, dangerous semiaquatic pit viper that inhabits lowland swamps and waterways of the southeastern US. When threatening, it opens its mouth wide to display the white interior. Also called water moccasin.

  • Agkistrodon piscivorus, family Viperidae

• 2 (also cotton mouth) informal dryness of the mouth:I often have cotton mouth and a headache when I wake up