disappointed at

disappointed at someone or something

 and disappointed in someone or something
becoming sad because of someone or something. I am really disappointed at what you did. I am very disappointed in you. That was a terrible thing to do. They were disappointed in the outcome.
See also: disappointed
References in classic literature ?
returning to his letter, she was disappointed at the outset.
All hailed Don Quixote as victor, but the greater number were vexed and disappointed at finding that the combatants they had been so anxiously waiting for had not battered one another to pieces, just as the boys are disappointed when the man they are waiting to see hanged does not come out, because the prosecution or the court has pardoned him.
I fancy the popular ex- pectation of a heap of charred corpses was disappointed at this inanimate bulk.
A LEADING Coventry city councillor has said he is disappointed at the number of retailers still selling knives and aerosols to underage children.
I am not disappointed at all at not winning,'' said Harrington.
Disappointed at his father's failure to show up at his birthday, Justin wishes that for at least one day his dad would have to tell the truth.
TRADE GROUP DISAPPOINTED AT CHANDLER, DICKS, GORTON EXPORT BAN BILL
Toliver went on to add, "While we are disappointed at this news, it will not have a material impact on our other operations or earnings.