fly
In real, traceable use. Part of the curated seed collection; community review is coming.
Sense 1
Meaning · English
Quick-witted, alert, mentally sharp.
Register: dated, slang
Where it’s used:
Used
American English
Examples
be assured, O man of sin—pilferer of small wares and petty larcener—that there is an eye within keenly glancing from some loophole contrived between accordions and tin breastplates that watches your every movement, and is "fly,"— to use a term peculiarly comprehensible to dishonest minds—to the slig
Usage example from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30)
Sources & notes
Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30 via kaikki.org).
Sense 2
Meaning · English
Clandestine, surreptitious
Register: slang
Sources & notes
Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30 via kaikki.org).
Sense 3
Meaning · English
Well dressed, smart in appearance; in style, cool.
Register: slang
Sources & notes
Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30 via kaikki.org).
Common questions
What does “fly” mean?
Quick-witted, alert, mentally sharp.
Is “fly” formal or informal?
fly is generally dated, slang.