From Cantonese 白牌, literally ‘white numberplate’.
pak pai (plural pak pai or pak pais)
- (now historical) A car used as an illegal taxi in Hong Kong. [from 20th c.]
- 1977, John Le Carré, The Honourable Schoolboy, Folio Society 2010, p. 471:
- He took pak-pais, knowing they were less under the thumb of the police.