A person who discriminates against or holds prejudice toward people based on their age; one who practices ageism.
From 'ageism' with the agent suffix '-ist' (from Latin '-ista'), meaning 'one who practices or believes in.' Created in the same period as ageism in the 1960s-70s civil rights discourse.
The word 'ageist' is interesting because it names something—person-shaped prejudice—that society accepts more readily than we'd accept equivalents for other identities, revealing what biases we still consider acceptable.
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