Definition of blacking up in English:

blacking up

noun

  • The action, process, or practice (by a white person) of applying dark colour to the face (and sometimes also the body), typically in order to play the role of a black person.

Origin

Mid 19th century (in an earlier sense). From blacking + up.

Pronunciation

blacking up

/ˌblakɪŋ ˈʌp/