/ Thesaurus / B Synonyms of barnaby's thistle Find synonyms for: Noun1. Barnaby's thistle, yellow star-thistle, Centaurea solstitialis, weedusage: European weed having a winged stem and hairy leaves; adventive in the eastern United StatesWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: sequester Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language