truth serum

American

[trooth seer-uhm] / ˈtruθ ˌsɪər əm /

Often truth drug

noun

a drug, as the barbiturate thiopental, that induces in the subject a desire to talk or a state of heightened suggestibility, used in psychotherapy and in interrogation to discover repressed or consciously withheld information.

First recorded in 1920–25

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023