The quality or state of being crispy; the degree to which something is crisp or brittle.
From 'crispy' plus the noun-forming suffix '-ness,' which creates abstract nouns describing qualities. This is one of English's most productive ways to make nouns: happy → happiness, quick → quickness.
The suffix '-ness' is so powerful that you can almost add it to any adjective to create a noun, which is why it's the favorite tool of scientists coining new descriptive terms.
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