Boy's play

childish amusements; anything trifling.

See also: Boy

References in classic literature ?
Man does some of his part of the exchange work in his six weeks of haying, and it is no boy's play.
She was fond of all boy's plays, and greatly preferred cricket not merely to dolls, but to the more heroic enjoyments of infancy, nursing a dormouse, feeding a canary-bird, or watering a rose-bush.
Anton and Luke's noise attracts the attention of a little dog that tries to join in the boy's play.