Как по Английски будет 愣头愣脑

adjective

Heedless of danger or the consequences of one's actions; rash or impetuous.

Примеры использования:

You mustn't be so reckless

adjective

Acting or done quickly and without thought or care.

Примеры использования:

She might live to rue this impetuous decision

adjective

Acting or done without careful consideration of the possible consequences; impetuous.

Примеры использования:

It would be extremely rash to make such an assumption

noun

An area of redness and spots on a person's skin, appearing especially as a result of allergy or illness.

Примеры использования:

A red itchy rash appeared on her legs