danger sign

All at once the girls understood the meaning of Janes danger sign.

Outside appearances sometimes do not show the interior condition, but one should regard a fungus as a danger sign.

And Polly sucked in her under lip, a danger sign that she was angry.

The danger sign of peasantry is a degraded standard of life.

I guess we'll run up my red parasol on the end of an oar for a danger sign.