lie detector

noun

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

Synonyms

• 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

Authorities interviewed and administered lie detector tests to students, teachers and even Hartley's father. —Samantha Stutsman, PEOPLE, 7 Oct. 2025

This one has all the family secrets, betrayal and a sibling who acts as a human lie detector. —Kail Lowry, People.com, 23 Aug. 2025

The all-night stream included a wide array of activities to promote donations and keep people engaged, including taking lie detector tests, being covered by snakes, getting haircuts, and oil wrestling. —Nick Mordowanec jason Lemon, MSNBC Newsweek, 15 Aug. 2025

Every action, whether minor or major, is followed by another lie detector test to confirm continued loyalty. —Yossi Melman, ProPublica, 7 Aug. 2025

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