be off (one's) guard

To not be especially careful or vigilant; to not be prepared for danger or surprises. We'll wait until he's off guard, and then we'll take him and his company for all they're worth! Don't be off your guard, there are a lot of suspicious characters around here!

Common Names:

Name	Pronounced	Usage
Silvie	-	Czech
Giustina	joos-TEE-nah	Italian
Arden	AHR-dən	English
Eutychus	-	Biblical, Biblical Latin
Daryawesh	-	Biblical Hebrew
Griffith	['grifiθ]