1. strengthen Confirm (L. con, together, and firmus, firm) is to add firmness or give stability to. Both confirm and corroborate presuppose something already existing to which the confirmation or corrobo Synonyms: confirm, assure, fix, sanction, substantiate, corroborate, prove, settle, sustain, establish, ratify, strengthen, uphold Antonyms: abrogate, cancel, overthrow, shatter, upset, annul, destroy, shake, unsettle, weaken, condole with, console
Synonyms for strengthen 
