They remembered too keenly their pleasant credulity as to what to-morrow would bring forth, to dare indulge expectation of its pleasure; they had been disappointed once—so might they be again—for disappointment ever leaves fear behind.
1992, News Group Newspapers Ltd, Today:
Choking back his disappointment after his own team's splendid wins against Liverpool and Aston Villa, he said: "I've got to be humble and say we were beaten by a very good side."
(countable) An example or the act of disappointing: a circumstance in which a positive expectation is not achieved.
The disappointment with our trip to California caused bickering.
2012 May 5, Phil McNulty, “Chelsea 2-1 Liverpool”, in BBC Sport[1]:
For Liverpool, their season will now be regarded as a relative disappointment after failure to add the FA Cup to the Carling Cup and not mounting a challenge to reach the Champions League places.
1990, Peter Hennessy, Cabinet, Basil Blackwell Ltd:
As the disappointments crowded in — the economy, Rhodesia, strife within the trade-union movement — Wilson tried the expedient of a semi-formal inner Cabinet, or Parliamentary Committee, as he misleadingly liked to call it.
(countable) Something or someone that disappoints: that which causes disappointment.
Even a trip to beautiful California can be a disappointment.