What does blabbermouth mean?
A blabbermouth is a person who talks too much and, more specifically, cannot be trusted to keep a secret. The word carries an informal, mildly mocking tone: it is the sort of thing you might call a friend who let slip about a surprise party, rather than a term of serious condemnation. It combines 'blab', an old verb meaning to talk indiscreetly or reveal secrets, with 'mouth', giving a vivid image of someone whose mouth betrays them. Blabbermouth appears most often in casual conversation in both British and American English, frequently in warnings such as 'don't tell him, he's a blabbermouth'. While closely related to words like gossip and chatterbox, it differs from them: a gossip spreads other people's news, and a chatterbox merely talks a lot, whereas a blabbermouth is defined by leaking what should stay quiet. Its playful sound makes it a favourite in informal speech.
nounA person who talks too much, especially one who cannot keep a secret and reveals things that should be kept private.
- A person who habitually reveals secrets or private information by talking indiscreetly.
- More broadly, an excessively talkative person who chatters constantly.
"Don't tell Marcus about the surprise party — he's a total blabbermouth."
"I only mentioned the plan to Dana once, but the blabbermouth had already told half the office."
"My little brother is such a blabbermouth that we stopped telling him anything before his birthday."
Standard plural; used when referring to several people who cannot keep secrets.
"The office was full of blabbermouths, so no rumour ever stayed quiet for long."
The word 'blabber' has meant 'to talk foolishly' since the Middle Ages — so a blabbermouth is literally a mouth that babbles away your secrets.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of blabbermouth
Blabbermouth is formed from 'blab', a verb of imitative origin meaning to talk foolishly or betray secrets, which has been part of English since at least the sixteenth century, combined with 'mouth'. The reduplicated form 'blabber' reinforces the sense of continuous, indiscreet chatter. It belongs to a family of expressive English words for excessive or indiscreet speech, including 'blather', 'babble', and 'prattle'.
Related word forms
How blabbermouth is actually used
Blabbermouth is informal and slightly derogatory, though often used teasingly among friends rather than as a serious insult. It is common in both British and American English, particularly in everyday speech rather than formal writing.
Easily confused with blabbermouth
A chatterbox simply talks a lot without necessarily revealing secrets, whereas a blabbermouth specifically betrays confidential information.