In the 15th century, the word disappoint meant “to remove someone from appointed office.” Only later did the word take on its modern meaning of “fail to fulfill expectations.” This is part of a complete episode.
anticipointment n.— «It’s what I call “anticipointment.” […] You can’t make a promise and then have people feel you broke it, or you’re worse off than when you started. So now they just need to live up to it.» —“B...
heartsink n. a feeling of dismay or disappointment; in medical use, heartsink patient, a patient that is difficult or impossible to help. (source: Double-Tongued Dictionary)