a warning sign
one that shows something bad might be happening

[TahlilGaran] Dictionary of Contemporary English ▲

warning something that you say or do to tell people about danger, or to tell them not to do something:
All cigarette packets carry a government health warning.
She ignored her parents' warnings.
The army issued a warning that anyone who was out on the streets after dark was likely to be shot.
caution formal an official warning or a piece of advice telling you to be careful:
Caution: do not install electrical equipment near or around water sources.
The video begins with a caution that you must do some warm-up exercises first.
tip-off informal a warning that someone is about to do something, especially one given to the police about a crime:
Police were called to the hotel after a tip-off.
alert a warning to be ready for possible danger that may happen soon:
Twelve flood alerts have been issued to areas along the River Severn.
a fire alert
The ambulance services were on red alert (=they were ready to take action immediately).
advisory formal an official warning or notice that gives information about a dangerous situation:
The air pollution gets so bad on some days that health advisories are posted at park entrances.
caveat formal a warning that something may not be completely true, effective etc. Also used when pointing out that it is important to remember something:
The woman was offered treatment, but with the caveat that it had only a 30% chance of success.
One caveat is that you must take the goods back to the shop within 14 days.
There is one important caveat to this argument.
a warning sign
Don’t ignore the warning signs of stress.
a warning shot
Troops fired warning shots over the heads of demonstrators.
a warning light
Red warning lights were flashing.
a warning look/glance
She gave me a warning look, but I carried on.
a warning gesture
He put his finger to his lips in a warning gesture.

[TahlilGaran] English Thesaurus ▲