tocsin
warning bell

Small warning bells went off in the back of my mind.

Despite the warning bells going off in her head, she couldn't seem to make herself leave.

A little warning bell went off in the back of Logan's head.

Then the sound of the warning bell reached his consciousness.

The warning bell was ringing at the back of his mind again.

The warning bell must have brought everyone out looking for news or rumors.

That alone was enough to ring a few warning bells in my head, but I said nothing.

There was a warning bell going off in the back of his mind, and experience told him not to ignore it.

"This is the warning bell so that you can dress."

It remained thus, until the first warning bell began to ring.