/ Thesaurus / O Synonyms of opisthotonos Find synonyms for: Noun1. opisthotonos, spasm, cramp, muscle spasmusage: severe spasm in which the back arches and the head bends back and heels flex toward the backWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: reclusive Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language