red flag

I say being married is usually a red flag for me.

All of these can be red flags for any business.

But the language raised no red flags with the state.

"A little red flag would go up in my mind."

The firm's recent study has turned up red flags at a number of companies.

Two red flags means the water is closed to the public.

The computer system shows a red flag against those that need to be followed up with a phone call or visit.

The doctors say they look for red flags in body language.

And all this was, as we say, a big red flag.

The red flag came out once the rain was coming down hard.