making you feel disappointed► disappointing something that is disappointing makes you feel unhappy or dissatisfied, because it is not as good as you hoped it would be: · The team had a disappointing season.· Company profits this year have been very disappointing.
► be a disappointment something that is a disappointment does not happen in the way you hoped, or is not as good as you expected: · The holiday was a bit of a disappointment - it rained the whole time.be a disappointment to: · The election results were a disappointment to civil rights groups.be a great/major disappointment: · It was a great disappointment to my parents that I didn't go to university.
► not live up to (somebody's) expectations if an event or person does not live up to expectations , you expected them to be very good but in fact they are not: · I'm afraid as a husband I never really lived up to Kelly's expectations.· Despite the enormous cost of making it, the film didn't live up to expectations.fail to live up to (somebody's) expectations: · I failed to live up to my parents' expectations, particularly at school.
► be a letdown spoken if something is a letdown , you do not enjoy it as much as you expected: · The party was a real letdown.· After months of planning and anticipation, the Florida trip was kind of a letdown.
► be an anticlimax/be anticlimactic something that is an anticlimax or is anticlimactic does not seem very exciting or interesting because it comes after something that was much better: · Going back to work after a month travelling in China is bound to be an anticlimax.· Compared to the excitement of the earlier parts of the film, the ending was a little anticlimactic.
► be a non-event an event or occasion that is a non-event is disappointing because nothing interesting or exciting happened: · Sue's party was a total non-event. Only five people turned up.
► be a bummer spoken informal if you say that a situation or event is a bummer , you mean it is very disappointing: · "I heard Reggie's going to quit the team." "That's a bummer."bummer! American: · "The party was last Saturday." "Oh, bummer! I always miss those things."
► something is not all it's cracked up to be informal use this to say that something is not as good as people say it is: · Northbourne Leisure Centre isn't all it's cracked up to be, they don't even have a sauna.· Being a fashion model isn't all it's cracked up to be. It is extremely hard work.
informal an event, performance etc that is not as good as you expected it to be SYN disappointment: 
The end of the book was a real letdown. → let down at let1