dispirited
Feeling discouraged and lacking energy or hope about something.
Dispirited means feeling discouraged, disheartened, or drained of energy and hope. When you're dispirited, it's like someone let the air out of your balloon: you lose your enthusiasm and motivation for what you were doing.
You might feel dispirited after studying hard for a spelling bee only to get eliminated in the first round. A soccer team could become dispirited after losing several games in a row, finding it harder to practice with the same energy they once had. The word captures that deflated feeling when setbacks or disappointments make you wonder if your efforts matter.
Notice that dispirited is different from just being tired or sad. It specifically describes losing your spirit, that inner spark that keeps you excited and engaged. A dispirited student might still go through the motions of doing homework but without any real interest or hope that things will improve.
The opposite of feeling dispirited is feeling inspired or spirited: full of energy and determination. When you're working on something you care about and things are going well, you feel spirited. But when obstacles pile up or you face repeated failures, you can become dispirited, and getting that spirit back can require encouragement, rest, or remembering why you started in the first place.