the quality or state of being dirty; the presence of dirt, filth, or uncleanness.
From the adjective 'dirty' plus the noun-forming suffix '-ness,' which creates abstract nouns denoting qualities or states. The '-ness' suffix is one of the most productive noun-forming tools in English, dating back to Old English.
The suffix '-ness' is so common that English speakers can add it to almost any adjective to make it a noun—'happiness,' 'sadness,' 'blueness'—which means English is constantly creating new words while using ancient grammar rules!
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