let (one's) guard down

(redirected from let his guard down)

let (one's) guard down

To become less guarded or vigilant; to stop being cautious about potential trouble or danger. Also worded as "let down (one's) guard." We'll wait long enough for them to let their guard down before we launch our invasion. There will always be people in this business looking to exploit you, so you can never let your guard down.
See also: down, guard, let