unhappy because something that you hoped for or expected did not happen or because someone or something was not as good as you expected
disappointed (that): She was disappointed that he never replied to her letter.
disappointed at/by/about: Obviously, I feel very disappointed at not getting the job.
disappointed in: I’m really disappointed in you, Ruth.
bitterly disappointed (=extremely disappointed): Ireland were bitterly disappointed to end the competition with only two points.
Synonyms and related words