warning flag
Sign of trouble
A warning flag is a signal that something may be wrong or dangerous.
The phrase comes from literal flags—red flags on beaches indicating unsafe swimming, yellow flags in racing signaling caution.
Figuratively, a warning flag is any sign that should prompt attention or concern: His evasiveness about money was a warning flag.
Often interchangeable with red flag.
- red alertTop emergency warning state
- danger signAlert marking a hazard
- alertWarning or watchfulness
- cautionCareful attention to risk
- proceed with cautionContinue while staying vigilant
danger · signal · smoke signal · alarm · false alarm · sign · omen · canary in the coal mine · indicator · hazard · flare · beacon · siren · checkpoint · referee · penalty · yellow card · semaphore
- beach safetylifeguard, rip current, no swimming, lifeguard tower, water safety
- nautical signalssemaphore, substitutes, distress signal, distress signals, SOS
warning flagall-clear
Signal danger has passed
green light · good sign · seal of approval · thumbs up · clean bill of health
warning flagclean slate
Record wiped clear
smooth sailing · clear skies · hidden danger · false positive
warning, flag, warn, warned, warns, warnings, flags, flagged, flagging