Meaning of “disappointment” - Learner’s Dictionary

disappointment

noun uk us /ˌdɪsəˈpɔɪntmənt/
FEELING [ U ]

B1 the feeling of being disappointed:

She couldn't hide her disappointment when she lost.
PERSON/THING [ C ]

B1 someone or something that disappoints you:

I'm sorry I'm such a disappointment to you.

(Definition of “disappointment” from the Cambridge Learner’s Dictionary © Cambridge University Press)