Watch your back

Meaning

Be careful and stay alert for danger.

Usage

Used when warning someone about potential betrayal.

Origin & History

Origins and dates here are approximate summaries. Many idioms have disputed or unknown origins, and not every date has been checked against a historical dictionary, so treat specific dates and stories as a starting point rather than a citation.

Military and streetwise caution to guard vulnerable areas.

Used widely in cautionary advice since the 20th century.