Stay alert always.

Meaning: This means to remain watchful and attentive at all times. It's like saying, Always pay attention to your surroundings.

Choice of Words: Stay is a verb that means to remain in a particular place or state. Alert is an adjective that describes a state of being watchful and attentive. Always is an adverb that means at all times or continuously.

Alternative Expressions

Keep your eyes peeled.

Meaning: This means to be very attentive and observant, and to watch for anything unusual.

Choice of Words: Keep is a verb that means to hold or maintain something. Eyes are the organs that allow us to see. Peeled means to open wide, like when you peel an orange. When you put them together, "Keep your eyes peeled" means to keep your eyes open and focused.

Don't let your guard down.

Meaning: This means to stay cautious and alert, and not to become careless or overconfident.

Choice of Words: Don't is a contraction of the words "do" and "not". Let is a verb that means to allow something to happen. Guard is a noun that refers to a person or thing that protects something. Down means to lower or reduce something. When you put them together, "Don't let your guard down" means to not lower your level of protection or vigilance.

Related Expressions