The quality or state of being angry; a feeling of intense displeasure or rage.
From angry plus the suffix -ness, which transforms adjectives into abstract nouns representing qualities or states. This follows the productive English pattern of creating nouns from adjectives.
The suffix '-ness' is one of English's most ancient productivity tools—it appears in Old English and allows speakers to instantly create new nouns, which is why 'angriness' feels natural even though we more often say 'anger.'
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