Meaning
A positive sign that a person or situation is likely healthy, safe, or worthwhile, especially a trait that makes a potential partner or friend seem like a good bet. Informal, internet-flavoured opposite of the warning-sign idiom; affectionate rather than mocking in tone. Warm, informal, and internet-flavoured; almost always used approvingly. Regional use: General English; strongest in online dating talk.
Origin
Merriam-Webster's slang entry defines it as the direct opposite of red flag, noting that the warning-sign idiom has been current since at least the mid-1700s, and states plainly that it is unclear when the metaphorical sense of the positive form arose. The colour logic is older than the slang: green has long marked go, safe passage, and all-clear in literal signals, as Cambridge's entry records for race starts and safe swimming beaches. Inference rather than record: the dating usage appears to have grown in late-2010s and 2020s social-media discourse about relationships, riding the same wave of flag talk that produced the 2021 red-flag emoji meme and offshoots such as beige flag.
Research Sources
References used to check this entry’s meaning, history, or documented forms.
Variants
- a total green flag
- giving off green flags
- green flags
- green-flag (modifier)
Usage Examples
- Remembering how you take your coffee after one visit is a green flag.
- The way your new friends ask follow-up questions is a green flag for the whole group.
- Honestly, apologising first after an argument is a green flag in any roommate.