fast one

In real, traceable use. Part of the curated seed collection; community review is coming.

Meaning · English

A trick or deception.

Register: slang

Where it’s used: Used American English

Examples

The salesman tricked me into paying twice for the same thing. That was a fast one!

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 “fast one” mean?

A trick or deception.

Is “fast one” formal or informal?

fast one is generally slang.