for no reason 平白无故

“平白无故”，汉语成语，指无缘无故、没有理由或原因。可以翻译为“for no reason，without reason or cause或for no apparent reason”等。

例句：

平白无故挨了顿骂

Get a scolding for no reason at all

她不可能平白无故离开他。

It was impossible that she left him for no reason at all.