Breadcrumb Home > Thesaurus > C Synonyms of castor bean Find synonyms for: Noun1. castor bean, oilseed, oil-rich seedusage: the toxic seed of the castor-oil plant; source of castor oilWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. ✖ Related Content Daily Word Quiz: hortatory Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language