To dishearten means to cause someone to lose confidence, hope, or enthusiasm. When you become disheartened, something has made you feel discouraged or less sure that things will work out.

Imagine practicing free throws every day for weeks, determined to make the basketball team. Then tryouts arrive and you miss shot after shot while others sink theirs easily. That sinking feeling in your chest, that sense that maybe you're not good enough after all: that's what it means to feel disheartened. The failed tryout has disheartened you.

A string of rejection letters can dishearten a writer. Watching a carefully built tower collapse can dishearten a young engineer. Losing three games in a row can dishearten a soccer team. The word captures that particular moment when difficulty or failure makes you wonder whether continuing is worth the effort.

Notice that being disheartened can be temporary, even though it doesn't feel that way at the time. The basketball player who feels disheartened after a bad tryout can practice more and try again. The writer keeps submitting stories. The opposite of disheartened is encouraged or heartened, when something renews your confidence and energy to keep going.