The quality or state of being decorous; propriety, dignity, and good taste in behavior or appearance.
From decorous + -ness. Decorous derives from Latin decorus (fitting, proper, becoming). The -ness suffix is one of the oldest productive suffixes in English, dating to Old English.
Victorian literature absolutely loved words like 'decorousness'—it captured the obsession with correct behavior and propriety that defined the era. Interestingly, 'decorousness' was more about *behavior* being tasteful than about *rooms* being pretty, showing how the same word family branched into completely different meanings.
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