Three may keep counsel, if two be away.

The proverb treats secrecy as increasingly fragile when more people share confidential information. Its pointed arithmetic suggests that one person can guard a confidence more reliably than three can.

It also expresses skepticism about promises of discretion: even trusted people may disclose what they know. The saying does not require a literal group of three; its force lies in the contrast between a shared secret and one kept alone.

Use it to warn against telling several people something that must remain private, or to comment wryly after a confidence has spread. It can sound distrustful, so it may be ill-suited to a conversation where reassurance is needed.