Plain form
disappoint

Third-person singular
disappoints

Past tense
disappointed

Past participle
disappointed

Present participle
disappointing

(transitive & intransitive) If something disappoints somebody, it makes them unhappy because it was not as good as they expected.
I'm afraid you really disappointed me. I thought you were more honest.

We thought the party would be good and it didn't disappoint.
(transitive & intransitive) If something disappoints somebody, they thought it would happen but it didn't.
I'm sorry to disappoint you, but the meeting has been cancelled.

When the president returned, it disappointed our hopes for change.

Verb