Synonyms for Substantiate (same or very similar meaning)
WordNet sense 1 (represent in bodily form):
embody, incarnate, body forthWordNet sense 2 (make real or concrete; give reality or substance to):
actualize, realize, actualise, realiseWordNet sense 3 (establish or strengthen as with new evidence or facts):
affirm, confirm, corroborate, support, sustainFrom the ODE community, based on WordNetadd/edit