a red flag

Значение

a sign that something may be wrong or dangerous

Тревожный признак, предупреждающий сигнал, повод насторожиться.

Примеры

1. 1A landlord who won't show you the flat before you pay is a red flag.
2. 2The missing reviews were a red flag, so we booked a different hotel.
3. 3When the seller asked me to pay in cash before I'd seen the car, that was a red flag.
4. 4Is it a red flag if a new friend never lets you meet their other friends?
5. 5The sudden silence in the team chat was a red flag that something had gone wrong.

Грамматика

Исчисляемое: a red flag, во множественном числе red flags. Часто после be, see или raise.