blow the gaff
In real, traceable use. Part of the curated seed collection; community review is coming.
Sense 1
Meaning · English
To disclose a secret.
Register: slang
Examples
But, my child, if Geoffrey is to be got out at this immature stage it blows the gaff completely. Half of the crowd will vanish, including all the worst, and we shall have no proof at all of the real depths of the conspiracy.
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). Figurative class: Metaphor (PIE-English corpus, CC BY 4.0, retrieved 2026-07-31).
Sense 2
Meaning · English
To inform against a person.
Register: slang
Sources & notes
Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30 via kaikki.org).
Common questions
What does “blow the gaff” mean?
To disclose a secret.
Is “blow the gaff” formal or informal?
blow the gaff is generally slang.