In a childish or childlike manner.

child-like, adv. in child-like manner.

With reference to a person who is no longer a child: in a manner not befitting maturity; in a puerile, foolish, or silly way.

In the manner of a baby or young child; esp. in an unduly childish manner; babyishly.

in a puerile fashion; childishly.

In the manner of a baby or young child; (excessively) childishly. Cf. earlier babishly, adv.

= babyishly, adv.