Definition of big boy in English:

big boy

noun

  • 1informal A boy who is relatively old or mature; (also) a boy who is old enough to look after himself or to cope with adult experiences (also (informal) used ironically, of a man).

  • 2informal Informal. A form of address for a man, especially indicating familiarity or approval.

  • 3US
    informal Informal (originally US). An important or influential man; (also) a leading figure, organization, etc.; a major player. to play with the big boys: to compete at the highest level, especially precociously or prematurely.

  • 4A piece of heavy artillery.

  • 5A nuclear weapon; an atom bomb or a hydrogen bomb.

Origin

Late 16th century; earliest use found in John Higgins (b. c1544), poet and linguist. From big + boy.

Pronunciation

big boy

/ˈbɪɡ ˌbɔɪ/