An instrument designed to detect when a person has answered a question falsely.
A polygraph used on persons suspected of lying: it records certain physiological changes assumed to occur when the subject lies in answering questions.
Webster's New World
Other Word Forms of Lie Detector
Lie Detector Sentence Examples
While there really isn't a definite way to tell if someone is lying unless you catch him in the act or have him take a lie detector test (and even these tests can be wrong), you can become your own personal detector with a few techniques.
Players must be careful how they answer the questions on the cards, or they may be forced to take the lie detector test to expose the truth.
To win, score the most points by answering questions honestly, or out smarting friends and the Lie Detector!
Gene takes a lie detector test on the Adam Corolla show, to prove once and for all whether or not his claims of sexual prowess are true.
On one episode of her show, she was attached to a lie detector and asked "Are you jealous of Oprah Winfrey?"