/ Thesaurus / S Synonyms of seismal Find synonyms for: Adjective1. seismic, seismal, unstable (vs. stable)usage: subject to or caused by an earthquake or earth vibrationWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: supine Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language