red flag

NOUN

warning signal

Synonyms

WEAK

casus belli delicate subject red light red rag sore point

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The incident happened at Station Corner and a red flag brought the session to a close.

From BBC • May 7, 2026

So this retreat is a bit of a red flag.

From Barron's • May 4, 2026

A contractor who offers to do the job without a building permit is a red flag.

From The Wall Street Journal • Apr. 25, 2026

That is always a red flag for me when I’m reading an OLC opinion.

From Slate • Apr. 9, 2026

“That guy’s a walking red flag, Lexie. He’s not good for you.”

From "Red Flags and Butterflies" by Sheryl Azzam