Espionage vs Intelligence vs Surveillance

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

Espionage

FormalTop 5,000 (fairly common)

Intelligence

Top 1,000 (very common)B1noun

Surveillance

FormalBeyond 10,000 (less common)C1noun
Most common: Intelligence
 EspionageIntelligenceSurveillance
Pronunciation🇬🇧 //ˈɛspiənɑːʒ//🇺🇸 //ˈɛspiəˌnɑʒ//🇬🇧 /["/ɪnˈtelɪdʒəns/"]/🇺🇸 /["/ɪnˈtelɪdʒəns/"]/🇬🇧 /["/sɜːˈveɪləns/"]/🇺🇸 /["/sɜːrˈveɪləns/"]/
MeaningThe secret act of spying, especially to get secret information.The ability to think, learn, and understand.Watching someone or something carefully, often to find out more information.
ExampleThe country was accused of conducting espionage against its neighbors.Her intelligence in solving complex problems is impressive.The police are keeping the suspects **under** constant **surveillance**.
RegisterFormalNeutralFormal
How commonTop 5,000 (fairly common)Top 1,000 (very common)Beyond 10,000 (less common)
CEFR level-B1C1
Part of speechnounnoun
Collocationsconduct espionage, engage in espionage, accuse of espionage, practice espionage, spy for espionageconsiderable, great, high, have, demonstrate, show, test, secret, good, reliable, collect, gather, get, agency, community, serviceclose, constant, regular, be under, keep somebody/​something under, place somebody/​something under, camera, device, equipment
Antonyms-ignorance, stupidityignorance, negligence, carelessness
Common mistakesConfused with 'spying' - espionage implies organized, often state-sponsored activities., Wrongly assume it's only about military - it can also involve corporate secrets.Often confused with 'intelligent' as a synonym., Misused as an adjective, though it is a noun., Sometimes incorrectly spelled as 'inteligence'.Confused with 'surveil' (verb) and 'surveillance' (noun), Mispronunciation, often as 'sur-veal-lance' instead of 'sur-veil-lance', Overusing in informal settings where more casual terms could fit
Usage notesUsed primarily in formal contexts, especially in discussions about government or military activities. Avoid in casual conversation.Used in both formal and informal contexts. Can refer to academic intelligence or general cleverness. Avoid using it in overly casual conversations.Used mainly in formal contexts such as law enforcement, security, and privacy discussions. Not appropriate in casual conversation. Can imply a sense of monitoring or intrusiveness.

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Espionage
Intelligence
Surveillance

Frequently asked questions: Espionage vs Intelligence vs Surveillance

What's the difference between Espionage, Intelligence, and Surveillance?

Espionage: The secret act of spying, especially to get secret information. Intelligence: The ability to think, learn, and understand. Surveillance: Watching someone or something carefully, often to find out more information.

Which is more common: Espionage, Intelligence, and Surveillance?

Intelligence is the most common in everyday English.

Which is more advanced: Espionage, Intelligence, and Surveillance?

Surveillance is the highest level, at C1, on the CEFR scale.

Can you show an example of each?

Espionage: The country was accused of conducting espionage against its neighbors. Intelligence: Her intelligence in solving complex problems is impressive. Surveillance: The police are keeping the suspects **under** constant **surveillance**.

Can I use Espionage, Intelligence, and Surveillance interchangeably?

Not always. Espionage, Intelligence, and Surveillance 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.