Breadcrumb Home > Thesaurus Cite Synonyms of stiffen Find synonyms for: Verb1. stiffen, changeusage: become stiff or stiffer; "He stiffened when he saw his boss enter the room"2. stiffen, change, alter, modifyusage: make stiff or stiffer; "Stiffen the cream by adding gelatine"3. stiffen, tighten, tighten up, constrain, restrict, restrain, trammel, limit, bound, confine, throttleusage: restrict; "Tighten the rules"; "stiffen the regulations"WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved.See also: stiffen (Dictionary) Related Content Daily Word Quiz: erpsichore Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language Synonyms Index