/ Thesaurus / L Synonyms of lethargic encephalitis Find synonyms for: Noun1. sleeping sickness, sleepy sickness, epidemic encephalitis, lethargic encephalitis, encephalitis lethargica, encephalitis, cephalitis, phrenitisusage: an encephalitis that was epidemic between 1915 and 1926; symptoms include paralysis of the extrinsic eye muscle and extreme muscular weaknessWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: magnanimous Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language