Definition of blackmouth in English:

blackmouth

noun

  • 1A foul-mouthed person; a slanderer. Now rare.

  • 2Attributive Designating the black-mouthed dogfish, Galeus melastomus.

  • 3United States regional. The chinook salmon, Oncorhynchus tshawytscha; specifically an immature one.

Origin

Mid 17th century. From black + mouth.

Pronunciation

blackmouth

/ˈblakmaʊθ/