lie detector

noun

1. a polygraph used to determine changes in certain body activities, as blood pressure, pulse, breathing, and perspiration, the results of which may be interpreted to indicate the truth or falsity of a person’s answers under questioning.

noun

1. a polygraph used esp by a police interrogator to detect false or devious answers to questions, a sudden change in one or more involuntary physiological responses being considered a manifestation of guilt, fear, etcSee polygraph (def. 1), galvanic skin response

n.

1. A polygraph used to detect possible deception during an interrogation.