strengthen

Synonyms: add add fuel to fire anneal ascend bolster brace build up buttress confirm corroborate empower enhance enlarge establish extend fortify harden heighten increase intensify invigorate justify make firm mount multiply regenerate reinforce rejuvenate renew restore rise set up sinew steel step up substantiate support sustain temper tone tone up toughen wax

Antonyms: break down hurt weaken

Synonyms: animate back back up bear out bloom brace brace up burgeon carry weight cheer consolidate embolden enhearten enliven flourish flower fortify gather resources gird give weight harden inspirit invigorate nerve nourish prepare prosper rally ready refresh rejuvenate restore steel substantiate temper thrive toughen uphold

Antonyms: discourage dishearten dissuade weaken