1. In a childish manner.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• childishy,
• childished,
• chidishly,
• childlishly,
• xhildishly,
• vhildishly,
• fhildishly,
• dhildishly,
• cgildishly,
• cbildishly,
• cnildishly,
• cjildishly,
• cuildishly,
• chilishly,
• childshly,
• chilldishly,
• childdishly,
• chillishly,
• childishley,
• hilishly

• cheilitis,
• childishness,
• childish.

The adjective form of the word "childishly" is "childish".