Definition of blue skin in English:

blue skin

noun

North American
slang
  • 1Derogatory. A black person or a person of mixed black and white descent. Now rare.

  • 2Derogatory (now historical). A nickname for: an excessively moralistic person; a Presbyterian.

Origin

Late 18th century (in an earlier sense). From blue + skin.

Pronunciation

blue skin

/ˈbluː skɪn/