Also found in: Dictionary, Thesaurus, Medical, Legal, Financial, Encyclopedia, Wikipedia.
1. verb, slang To arrest someone. The police will flag all of us if they catch us drinking—we are underage, you know.
2. verb, slang To fail something. You better study hard, or you'll flag this exam.
3. noun, slang The grade of F on something. You better study hard or you'll get a flag on this exam.
4. noun, slang A bandana worn to show one's gang affiliation. What color flag is that kid wearing?
To wave one's arms to attract someone's attention, usually to get them to stop moving. A noun or pronoun can be used between "flag" and "down." I was finally able to flag down a passing motorist to help with our stalled car. It'll take awhile to flag a taxi down. Why don't we just walk to the museum?
flag someone or something down
to signal or wave, indicating that someone should stop. Please go out and flag a taxi down. I'll be right out. She went to flag down a taxi.
Signal to stop, as in The police were flagging down all cars. This expression uses the verb flag in the sense of "catch the attention of, as by waving a flag," a usage dating from the mid-1800s; down was added in the first half of the 1900s.
To signal something or someone to stop: I flagged down a taxi when it started raining. When we ran out of gas, we flagged the police officer down to ask for help.
1. tv. to fail a course. Pat flagged English again.
2. n. the grade of F. I’ll get a flag on algebra for the semester.
3. tv. to arrest someone. (see also flagged.) They flagged Bob for speeding even though he was a judge.
4. n. a headcloth or bandana, especially one that shows gang identity. (Streets.) The kid wore a “flag” that alerted the officers to the fact that he was a gang member.