What does blab mean?
To blab is to let slip information that was meant to be kept private — typically not out of malice, but through careless, excessive, or indiscreet talk. The word carries strong negative connotations: calling someone's remark 'blabbed' implies they were untrustworthy with a confidence, and telling someone not to blab is a familiar way of enforcing secrecy. The verb is firmly informal, appearing in everyday conversation far more than in formal writing, and it pairs naturally with phrases like 'blab a secret' or 'blab to the press.' English also derives from it the noun 'blab,' meaning a habitual revealer of secrets, though this sense has largely been replaced by the livelier compound 'blabbermouth.' With roots stretching back to Middle English and a sound that seems to mimic idle chatter itself, 'blab' remains a vivid, useful word for describing exactly how secrets escape: one loose sentence at a time.
To reveal secret or private information carelessly or indiscreetly, especially by talking too much.
"He blabbed the whole plan before the meeting even started."
Informal; often used with an object ('blab a secret') or with 'to' indicating the listener ('blab to his friends').
A person who habitually reveals secrets or talks indiscreetly.
"I can't believe you told her — she's a notorious blab."
This noun sense is now dated; 'blabbermouth' is the more common modern equivalent.
The plural applies only to the rare noun sense meaning a person who reveals secrets; the verb does not have a plural form.
"The office was full of blabs, so nothing stayed confidential for long."
Before it meant spilling secrets, 'blab' was essentially an imitation of the sound of someone chattering on and on — the word itself gossips.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of blab
'Blab' originated in Middle English, where the verb 'blabben' meant to talk foolishly or indiscretely. Its origins are generally considered expressive or imitative in nature, echoing the sound of continual chatter, which places it in a family of English words formed by mimicking speech sounds. It has been used in its modern sense of indiscreetly revealing secrets since at least the early modern period, and it later gave rise to derivatives including 'blabber' and the compound 'blabbermouth.'
Related word forms
How blab is actually used
'Blab' is informal and carries a distinctly negative connotation, implying thoughtlessness or untrustworthiness rather than deliberate betrayal. It is most common in everyday speech and rarely appears in formal writing. The noun sense ('a blab') is now somewhat dated; 'blabbermouth' is the more current term for such a person.
Easily confused with blab
While 'blab' means to reveal secrets through careless talk, 'blubber' means to weep noisily (or refers to whale fat); the two are unrelated in meaning despite similar sound.