CHILDISHLY

childishly

(adverb) in a childlike manner; “he acted very childishly”

Source: WordNet® 3.1

Etymology

Adverb

childishly (not comparable)

In a childish manner.

Source: Wiktionary

Child"ish*ly, adv.

Definition: In the manner of a child; in a trifling way; in a weak or foolish manner.

CHILDISH

Child"ish, a.

1. Of, pertaining to, befitting, or resembling, a child. "Childish innocence." Macaulay.

2. Peurile; trifling; weak. Methinks that simplicity in her countenance is rather childish than innocent. Addison.

Note: Childish, as applied tc persons who are grown up, is in a disparaging sense; as, a childish temper.

Source: Webster’s Unabridged Dictionary 1913 Edition