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

Kardashian inspired even more backlash after the internet noticed that the gown appeared to have been damaged during the event — though the star denied causing any harm in a November 2025 lie detector video for Vanity Fair with her All's Fair costar Teyana Taylor. —Catherine Santino, PEOPLE, 2 May 2026

Basically, Tsimhoni says, the testing acts as a lie detector. —Kristin Shaw, Popular Science, 30 Apr. 2026

Would that statement hold up against a lie detector test? —Matt Schneidman, New York Times, 27 Apr. 2026

Though Earle left Cooper’s Unwell Network months before Johnson chimed in during her Vanity Fair lie detector test in June 2025, nothing was ever confirmed on what went down between the two women and why Earle parted ways with Cooper’s company in March 2025. —Carly Thomas, HollywoodReporter, 16 Apr. 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