Vigilant
adjective
Definition
1. (adjective) Carefully watching for possible danger, problems, or anything suspicious — staying alert and never letting your guard down.
Context Alive
You're travelling alone in a busy train station in a city you've never visited before. Your dad's voice echoes in your head: "keep your bag in front of you and stay vigilant." You hold your backpack close, check your surroundings every few minutes, and keep one hand on your phone in your pocket. A man bumps into you and apologises, and you immediately check your wallet. It's still there. You relax a little but keep your eyes open until you're safely on the train.
Meanings
1 meanings 1 Carefully Alert to Danger or Problems (Adjective) Common ▼
This meaning is about keeping your eyes and mind wide open — paying close attention to your surroundings because something could go wrong at any moment. Imagine a security guard working the night shift at a warehouse. It's dark, quiet, and nothing has happened for hours, but he stays vigilant — checking every camera, listening for unusual sounds, walking the perimeter. This is describing a state of constant, careful awareness. You might hear "police are urging residents to remain vigilant" after a series of burglaries in a neighbourhood, or someone could say "parents need to be vigilant about what their children do online" when discussing internet safety. Or picture a lifeguard at a crowded beach on a hot summer day — hundreds of people in the water, children running, waves getting stronger. She has to stay vigilant every second because one moment of distraction could cost a life. The word suggests the alertness is deliberate, sustained, and serious.
✏️ Vigilant sounds more serious and formal than "careful" or "alert." It's the word you hear in news reports, police statements, and official warnings. The noun form is vigilance: "we must maintain vigilance" — very common in security and health contexts. A vigilante is a related but different word — someone who takes the law into their own hands.
Common Patterns
Basic Structures
be/stay/remain vigilant → to keep yourself alert and watchful — the most common pattern
The police have asked everyone to remain vigilant after the incident.
vigilant about + noun/verb-ing → specifies what you need to watch carefully for
Parents should be vigilant about their children's screen time.
vigilant against + noun → staying alert to prevent a specific threat
The country must remain vigilant against cyber attacks.
Common Structures
ever vigilant → always on guard — emphasises the constant nature of the alertness
The coastguard remains ever vigilant, even on calm days.
need to be vigilant → a warning that careful attention is required
Travellers need to be vigilant in crowded tourist areas.
keep a vigilant eye on → to watch something or someone very carefully and continuously
The nurse kept a vigilant eye on the patient throughout the night.
Collocations
10 collocationsremain vigilant
to continue staying alert — very common in official warnings
stay vigilant
to keep watching carefully and not let your guard down
ever vigilant
constantly on guard — emphasises non-stop awareness
vigilant eye
careful, watchful observation of something or someone
vigilant about safety
paying close attention to potential safety risks
vigilant against threats
staying alert to prevent specific dangers
constant vigilance
non-stop alertness and attention — the noun form in action
maintain vigilance
to keep up a high level of awareness over time
heightened vigilance
an increased level of alertness — usually after a threat
need for vigilance
the importance of staying alert in a particular situation
Example Sentences
10 examples
1
Police are urging the public to remain vigilant following a series of break-ins in the area.
Police are asking residents to stay alert after several burglaries in the neighbourhood.
2
You need to be vigilant when using public Wi-Fi — hackers can steal your data easily.
You should be very careful on public Wi-Fi — it's easy for hackers to access your information.
3
The lifeguard stayed vigilant even when the beach seemed calm and empty.
The lifeguard kept watching closely even when the beach looked peaceful and quiet.
4
Parents must be vigilant about what their children are watching online.
Parents need to pay close attention to the content their kids consume on the internet.
5
Airport security staff are trained to be constantly vigilant for suspicious behaviour.
Airport security workers are trained to always watch for anything that seems unusual.
6
She kept a vigilant eye on her bag throughout the crowded market.
She watched her bag closely the entire time she was in the busy market.
7
The government has called for heightened vigilance against online fraud.
The government has asked people to be more alert than usual about internet scams.
8
He was always vigilant about locking the doors and windows before going to bed.
He always made sure to check every door and window was locked before sleeping.
9
In the wild, animals must be vigilant at all times to avoid predators.
In nature, animals have to stay constantly alert to escape being hunted.
10
The nurse remained vigilant throughout the night, checking the patient's vital signs every hour.
The nurse stayed alert all night, monitoring the patient's condition every sixty minutes.
Synonyms & Antonyms
6 items
Synonymsalert
more everyday and less formal — used in the same situations but feels lighter
watchful
very similar — implies keeping your eyes on something carefully
attentive
slightly softer — focuses more on paying attention than watching for danger
Antonymscareless
not paying attention and ignoring potential risks
negligent
more formal and serious — failing to take proper care, often with consequences
oblivious
completely unaware of what's going on around you