Synonyms of toughen

2 Syllables
harden, temper, season, tighten, anneals, strengthen, hardens, tightens, anneal, strengthens
3 Syllables
weathered, vitrify, strengthening, annealing, develop, pillared, tightening, weathering, tightened, annealed, reinforcing, inuring, vitrifying, pillaring, inure, inured, reinforce, strengthened, callouses, calloused
4 Syllables
rigidify, caseharden, acclimating, climatize, acclimate, indurating, indurated, indurate, acclimated, brutalize
5 Syllables
acclimatize