Be on your guard vs Keep watch

When to use each in English, with meaning, register, and examples.

Be on your guard

Top 2,000 (common)

Keep watch

Top 3,000 (common)
Most common: Be on your guard
 Be on your guardKeep watch
Pronunciation🇬🇧 //biː ɒn jɔː ɡɑːd//🇺🇸 //bi ɑn jʊr ɡɑrd//🇬🇧 //kiːp wɒtʃ//🇺🇸 //kiːp wɑtʃ//
Meaningto stay alert and carefulTo stay alert or pay attention, especially for danger.
ExampleYou should always be on your guard when walking alone at night.He was asked to keep watch over the campsite at night.
RegisterNeutralNeutral
How commonTop 2,000 (common)Top 3,000 (common)
Collocationsbe on your guard against, always be on your guard, be on your guard while travelingkeep watch over, keep a close watch, keep watch for, keep watch at night, keep vigilant watch
Antonymsdrop your guard, be careless, be inattentive-
Common mistakesConfused with 'be on guard for' which implies waiting for something specific., Using it in overly casual contexts may sound unnatural.Confused with 'keep an eye on', which suggests a less formal level of vigilance., Using inappropriately in passive voice, as 'watch kept' sounds unnatural.
Usage notesUse this phrase when warning someone to be cautious. It's not typically used in formal writing.Used when monitoring a situation or being vigilant. Appropriate in both formal and informal contexts when discussing safety or alertness.

See it in real clips

Be on your guard
Keep watch

Frequently asked questions: Be on your guard vs Keep watch

What's the difference between Be on your guard and Keep watch?

Be on your guard: to stay alert and careful Keep watch: To stay alert or pay attention, especially for danger.

Which is more common: Be on your guard and Keep watch?

Be on your guard is the most common in everyday English.

Can you show an example of each?

Be on your guard: You should always be on your guard when walking alone at night. Keep watch: He was asked to keep watch over the campsite at night.

Can I use Be on your guard and Keep watch interchangeably?

Not always. Be on your guard and Keep watch are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.