The quality or state of being guilty; the feeling or fact of having done something wrong.
From guilty + -ness (noun suffix that forms abstract nouns from adjectives). The -ness suffix comes from Old English and allows us to talk about qualities as things rather than states.
Guiltiness is interesting because it can mean two different things: the legal fact that you did something wrong, or the emotional feeling of guilt, which aren't always the same—you can feel guilty about something you didn't do!
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