flatline
Proposed by a contributor, not yet supported by evidence.
Meaning · English
To kill.
Register: slang
Where it’s used:
Used
American English
Examples
If looks could kill, Mona's sharp gaze would have flatlined him in one second.
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).
Common questions
What does “flatline” mean?
To kill.
Is “flatline” formal or informal?
flatline is generally slang.