lie detector

noun

: a polygraph for detecting physiological evidence (such as change in heart rate) of the tension that accompanies lying

Synonyms of lie detector

• polygraph

Examples of lie detector in a Sentence

The murder suspect failed a lie detector test.

hooked the suspect up to a lie detector before interrogating him about the robbery

Recent Examples on the Web

Maury Povich spent decades at the center of one of daytime television’s most polarizing phenomena, presiding over paternity tests, lie detector results and the kind of raw confrontations that defined the height of ’90s talk TV. —Dave Quinn, PEOPLE, 28 Jan. 2026

Turning truth into a literal currency through a lie detector test feels perfectly aligned with this year’s theme. —Annika Pham, Variety, 16 Jan. 2026

This year’s lie detector session will take place at Gothenburg – Nordstan from January 16 to 18 and at Olof Palmes plats from January 24 to 26. —Zac Ntim, Deadline, 12 Jan. 2026

There were a number of red flags throughout Ames' career — lie detector tests that showed deceptive answers, sudden unexplained wealth, poor job performance, alcohol abuse — but the CIA repeatedly missed or ignored the warning signs and promoted him to increasingly sensitive posts. —Caitlin Yilek, CBS News, 6 Jan. 2026

Word History

First Known Use

1909, in the meaning defined above

Rhymes for lie detector

• eigenvector
• bisector
• collector
• connector
• corrector
• defector
• deflector
• director
• dissector
• effector
• ejector
• elector

Kids Definition

lie detector

noun

: an instrument for detecting bodily changes (as an increase in heart rate) that are considered to go along with lying

Medical Definition

lie detector

noun

ˈlī-di-ˌtek-tər 

: a polygraph for detecting physiological evidence (as change in heart rate) of the tension that accompanies lying

Legal Definition

lie detector

noun

lie de·​tec·​tor

: an instrument for detecting physiological evidence of the tension that accompanies lying compare polygraph