Here's what rhymes with disappointment.

Consider these alternatives

frustration / operation dismay / may regret / yet expressed / best surprise / size disappointed / disjointed displeasure / never sorrow / tomorrow disappointments / appointments despair / their disappointing / pointing shame / same skepticism / given frustrations / relations shock / stock doubt / out consternation / information disbelief / believe grief / leave optimism / given elation / relation anxiety / variety humiliation / relation pessimism / given unease / these exasperation / operation