lie detector: meaning, definition, pronunciation and examples
B2Formal, Technical, Legal, Journalistic
Quick answer
What does “lie detector” mean?
A device or procedure used to attempt to determine whether someone is telling the truth.
Audio
Pronunciation
Definition
Meaning and Definition
A device or procedure used to attempt to determine whether someone is telling the truth.
Can metaphorically refer to any person, situation, or technique used to expose dishonesty or deception.
Dialectal Variation
British vs American Usage
Differences
The term is identical and primary in both varieties. The specific legal admissibility and procedural norms surrounding its use vary by jurisdiction rather than dialect.
Connotations
In both, carries connotations of police investigations, security screenings, and pop-culture interrogation scenes. May also connote pseudoscience or unreliability in some contexts.
Frequency
Similar frequency. More likely to appear in legal, crime, or security-related discourse in both regions.
Grammar
How to Use “lie detector” in a Sentence
to take a lie detector testto be given a lie detector testto be connected to a lie detectorthe lie detector indicated deceptionVocabulary
Collocations
Examples
Examples of “lie detector” in a Sentence
verb
British English
- N/A – not used as a verb.
American English
- N/A – not used as a verb.
adverb
British English
- N/A – not used as an adverb.
American English
- N/A – not used as an adverb.
adjective
British English
- The lie-detector results were inconclusive.
- He underwent a lie-detector examination.
American English
- The lie-detector test proved he was lying.
- She is a certified lie-detector operator.
Usage
Meaning in Context
Business
Rare. Potentially in high-security vetting for sensitive positions: 'The executive role required a lie detector test as part of the due diligence.'
Academic
Used in psychology, criminology, or forensic science papers discussing the validity and ethics of polygraphy.
Everyday
Used in conversation about crime shows, trust issues, or sensational news: 'They should make politicians take a lie detector!'
Technical
Precise term in forensic and security fields, often specifying the type (e.g., 'computerised voice stress lie detector').
Vocabulary
Synonyms of “lie detector”
Vocabulary
Antonyms of “lie detector”
Watch out
Common Mistakes When Using “lie detector”
- Incorrect article: 'He was given lie detector test.' Correct: '...a lie detector test.'
- Using as a verb: 'They will lie detector him.' Incorrect. Use: 'They will give him a lie detector test.'
FAQ
Frequently Asked Questions
No, they are not considered completely reliable and can produce both false positives (indicating lies when truth is told) and false negatives (failing to detect lies). Their admissibility as evidence in court varies widely.
In many jurisdictions, you cannot be legally compelled to take one, especially in criminal court proceedings. However, employers or government agencies (e.g., for security clearance) may require it as a condition of employment or access.
A traditional polygraph measures physiological responses like heart rate, blood pressure, respiration rate, and skin conductivity (sweating). The underlying assumption is that these responses change when a person is being deceptive.
Yes, it is a compound noun where the first noun ('lie') modifies the second ('detector'). It is typically written with a space, but can be hyphenated when used as a modifier before another noun (e.g., lie-detector test).
A device or procedure used to attempt to determine whether someone is telling the truth.
Lie detector is usually formal, technical, legal, journalistic in register.
Lie detector: in British English it is pronounced /ˈlaɪ dɪˌtɛktə/, and in American English it is pronounced /ˈlaɪ dɪˌtɛktər/. Tap the audio buttons above to hear it.
Phrases
Idioms & Phrases
- “His conscience was a better lie detector than any machine.”
Learning
Memory Aids
Mnemonic
LIE DETECTOR: A detective who LIES? No! It's a detector for LIES. Think of a machine that 'detects lies' like a metal detector finds metal.
Conceptual Metaphor
TRUTH IS A PHYSICAL OBJECT / DECEPTION IS A PHYSICAL SUBSTANCE (that can be detected by a machine).
Practice
Quiz
What is the most common technical synonym for 'lie detector'?