1. the feeling of sadness or displeasure caused by the failure of something to meet one's hopes or expectations
Usage: usually uncountable when referring to the emotion itself; countable when referring to specific instances or causes
2. a person or thing that fails to meet expectations or causes disappointment
Usage: countable; refers to the source of disappointment rather than the emotion

Examples

• She felt a wave of disappointment when she didn't get the job.
• The movie was full of disappointments for fans of the original book.
• His repeated disappointments made him reluctant to try again.
• The team's loss was a major disappointment to their supporters.
• Despite the disappointments along the way, she never gave up on her dream.
• The restaurant turned out to be one disappointment after another.
• Life is full of small disappointments that we must learn to accept.