/ Thesaurus / S Synonyms of subjoining Find synonyms for: Noun1. supplementation, subjunction, subjoining, expansion, expanding uponusage: the act of supplementingVerb1. subjoin, append, tag on, tack on, tack, hang onusage: add to the endWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: confectionery Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language