lower one's guard

Verb

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

Japanese Meaning

警戒心を緩める / 身を危険にさらす状態に自ら置く

It's easy to lower one's guard when people are polite, but you should stay cautious.

人が礼儀正しいと警戒心を緩めてしまいがちですが、注意を怠らないでください。

Sense（1）

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

lowers one's guard

（ present singular third-person ）

lowering one's guard

（ participle present ）

lowered one's guard

（ participle past ）

lowered one's guard

（ past ）