lower one's guard

lower one's guard (third-person singular simple present lowers one's guard, present participle lowering one's guard, simple past and past participle lowered one's guard)

1. To become less guarded; to allow oneself to become more vulnerable.

   Synonyms: drop one's guard, let one's guard down

   Antonym: keep one's guard up

   • 2026 January 26, Ben Blanchard, Roger Tung, “Taiwan monitoring 'abnormal' China military leadership changes after top general put under investigation”, in Michael Perry, editor, Reuters‎^[1], archived from the original on 26 January 2026:

     Taiwan is monitoring what it called "abnormal" changes to China's military leadership after its most senior general was put under investigation, and will not lower its guard as the threat level remains high, the defence minister said on Monday.

• “drop lower your guard”, in Cambridge English Dictionary, Cambridge, Cambridgeshire: Cambridge University Press, 1999–present.
• “lower drop your guard let your guard down”, in Collins English Dictionary.
• “drop lower let down your guard” (US) / “drop lower let down your guard” (UK) in Macmillan English Dictionary.