The quality or state of being covered with hair or having a lot of hair.
From Old English 'hær' (hair) + '-y' (adjective suffix) + '-ness' (noun suffix, from Proto-Germanic 'nassiz'). The '-ness' suffix turns any adjective into an abstract noun.
The '-ness' suffix is incredibly productive in English—you can add it to almost any adjective to create a noun describing that quality, which is why we can say 'hairiness,' 'sadness,' 'brightness,' and thousands of others.
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