Definition of old chap in English:

old chap

noun

British
  • 1Without necessarily connoting age, as a familiar form of address, chiefly to a man.

  • 2An older man; frequently mildly disparaging.

Origin

Early 19th century; earliest use found in James Fenimore Cooper (1789–1851), novelist. From old + chap.

Pronunciation

old chap

/ˌəʊl(d) ˈtʃap/