/ Thesaurus / T Synonyms of truth serum Find synonyms for: Noun1. truth serum, truth drug, intravenous anestheticusage: an intravenous anesthetic drug that has a hypnotic effect; induces relaxation and weakens inhibitions; is believed to induce people to talk freelyWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: grimace Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language