Definition of child's game in US English:

child's game

noun

  • Child's play. Chiefly (and now only) with indefinite article or no.

Origin

Late Middle English; earliest use found in Speculum. From child + game, reflecting various forms of the genitive plural and genitive singular of the first element.

Pronunciation

child's game

/ˈtʃʌɪl(d)z ɡeɪm/