The state or quality of being disappointed, discouraged, or having lost one's pride or confidence.
From crestfallen plus the suffix -ness (creating abstract nouns from adjectives), a compound building on the animal metaphor of a fallen crest.
This noun captures that sinking feeling when your hopes are dashed—it's one of English's most evocative words for disappointment because the image of a drooping bird crest is so universal!
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