Emily Dickinson Lexicon

IM-PRO-PRI'ETY, n. [Fr. improprieté, from L. improprius. See Improper.]

1. Unfitness; unsuitableness to character, time, place or circumstances; as, impropriety of behavior or manners. Levity of conduct is an impropriety in a religious assembly and at a funeral. Rudeness or forwardness in young persons before their superiors, is impropriety. Indecency and indecorum are improprieties.
2. Inaccuracy in language; a word or phrase not according with the established usages or principles of speaking or writing. Many gross improprieties, however authorized by practice, ought to be discarded. Swift