figure By ELVIS ONDIEKIbr Polygraph: An instrument for the simultaneous electrical or mechanical recording of several involuntary physiological activities including blood pressure, skin resistivity, pulse rate, respiration, and perspiration, used especially as a lie detector.That is the Collins dictionarys definition of the gadget that may soon join breathalysers in the list of the most ...Care for a game of truth or dare? Want to get the truth? With the USB Polygraph you get a real polygraph machine! Use this lie detector to determine the truth (80%-99% accuracy).Synonyms for polygraph at Thesaurus.com with free online thesaurus, antonyms, and definitions. Find descriptive alternatives for polygraph. Polygraph. An instrument used to measure physiological responses in humans when they are questioned in order to determine if their answers are truthful. Also known as a "lie detec