无心的英文：
casualness

Stepped on toes
无心之失

One has no intention to advance in personal attainment
无心进取

An unwitting mistake
无心的错误

The cloud emerges from between the peaks without intent or purpose
云无心以出岫

It was another mindless crime.
那是另一次无心的罪过。

I'm not in the mood for joking.
我无心开玩笑。

An unintentional mistake
无心之错

An unintentional pun.
出于无心的俏皮话

Cloud arises without design—an inadvertent act
云出无心

At the moment she had no appetite for gossip.
此时此刻她无心闲聊。

casual employment at a factory;a casual correspondence with a former teacher.
工厂的临时雇佣人员；与先前老师的不定期通信

A casual saunter around the shops.
逛商店。

He endued with casual dress.
他穿着便服。

To discuss in a casual or frivolous manner:
以漫不经心或琐碎的方式议论。

He acted as a casual browser.
他扮演一个闲逛的人。