red flag
Sign of trouble
A red flag is a warning sign or signal that something is wrong.
The phrase comes from actual red flags used to indicate danger—on beaches, railroads, or in military contexts.
Now it typically describes suspicious behavior or troubling indicators: His constant lying was a red flag.
In dating and relationships especially, red flags are early warning signs of problematic partners: Not mentioning any friends is a major red flag.
Careful attention to risk
- alarmUrgent warning signal
- alertWarning or watchfulness
- hazardSource of potential harm
- dangerExposure to harm
threat · omen · harbinger · portent · presage · foreshadow · indicator · sign
Unacceptable condition that ends talks
- toxicCapable of causing harm
- narcissistSelf-obsessed person
- manipulationUnderhanded control of others
- gaslightingManipulation causing self-doubt
controlling · jealousy · dishonesty · avoidance · boundary · incompatibility · mistrust · secrecy
Displayed strip with message
- pennantTapering nautical flag
- markerSomething that signals location
- beaconGuiding light source
- semaphoreFlag-based signaling system
indicator · visual · signalman · linesman · referee · official · racing · motorsport
Official restriction on something
- forbiddenNot allowed
- illegalForbidden by statute
- prohibitedOfficially not permitted
- restrictionLimit on action
taboo · off-limits · violation · penalty · disqualification · foul · infraction · ejection
caution
Careful attention to risk
danger · threat · omen · harbinger · portent · presage · foreshadow · indicator · sign · signal
dealbreaker
Unacceptable condition that ends talks
- toxicCapable of causing harm
- narcissistSelf-obsessed person
- manipulationUnderhanded control of others
gaslighting · controlling · jealousy · dishonesty · avoidance · boundary · incompatibility · mistrust · secrecy · ghosting
banner
Displayed strip with message
semaphore · indicator · visual · signalman · linesman · referee · official · racing · motorsport
ban
Official restriction on something
- forbiddenNot allowed
- illegalForbidden by statute
- prohibitedOfficially not permitted
restriction · taboo · off-limits · violation · penalty · disqualification · foul · infraction · ejection · stop
matador
Bullfight's fatal sword wielder
cape · muleta · corrida · charge · taunt · provoke · enrage · olé · picador · banderilla
- beach safetylifeguard, rip current, no swimming, lifeguard tower, water safety
- Color Idiomsblack sheep, blue moon, green light, white lie, golden rule
- dangersdanger, peril, hazard, risk, menace
- racing termsbackstretch, daily double, dead heat, exacta, false start
- warningswarning, alert, caution, danger, warning sign
- suspiciondistrust, suspicion, mistrust, suspiciousness, doubt
red flaggreen light
Authorization to proceed
go-ahead · all clear · seal of approval · thumbs up · stamp of approval
red flaggreen flag
Signal meaning proceed
good sign · reassurance · vote of confidence · good omen · proof of concept
red, flag, reddish, redness, flags, redden, reds, red light, flagging