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Webster 1913 Edition

Indecorum

Inˊde-co′rum

,
Noun.
[Pref.
in-
not +
decorum
: cf. L.
indecorous
unbecoming.]
1.
Lack of decorum; impropriety of behavior; that in behavior or manners which violates the established rules of civility, custom, or etiquette; indecorousness.
Syn. – Indecorum is sometimes synonymous with indecency; but indecency, more frequently than indecorum, is applied to words or actions which refer to what nature and propriety require to be concealed or suppressed. Indecency is the stronger word; indecorum refers to any transgression of etiquette or civility, especially in public.

Webster 1828 Edition

Indecorum

INDECO'RUM

,
Noun.
[L. in and decorum.] Impropriety of behavior; that in behavior or manners which violates the established rules of civility, or the duties of respect which age or station requires; an unbecoming action. It is sometimes synonymous with indecency; but indecency, more frequently than indecorum, is applied to words or actions which refer to what nature and propriety require to be concealed or suppressed.

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