The quality or state of opposing or reducing aggressive behavior or tendencies.
From 'antiaggressive' with the suffix '-ness', which creates abstract nouns from adjectives. This noun form allowed speakers to discuss aggression-reduction as a character trait or policy goal in the 20th century.
Notice how '-ness' endings let us convert qualities into countable, discussable things—we can measure, evaluate, and debate 'antiaggressiveness' as a concept, which is why it became useful in psychology and diplomacy.
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