The principles, character, or conduct idealized as typical of a gentleman; adherence to the standards of gentlemanly behavior and character.
From gentleman plus the suffix -ism (denoting a system of beliefs or practices). This term emerged to name the whole philosophy and code of conduct associated with gentlemanly ideals.
'Gentlemanism' is interesting because it treats being a gentleman like an ideology or movement, similar to how we talk about feminism or capitalism. This shows how profoundly social classes were organized around codes of behavior that felt almost religious in importance.
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