Etymology
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improper (adj.)
mid-15c., "not true," from Old French impropre (14c.) and directly from Latin improprius "not proper," from assimilated form of in- "not, opposite of" (see in- (1)) + proprius (see proper). Meaning "not suited, unfit" is from 1560s; that of "not in accordance with good manners, modesty, or decency" is from 1739. Related: Improperly (late 14c.).
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impropriety (n.)
1610s, "quality or fact of being improper," from French impropriété (16c.) or directly from Latin improprietas "impropriety," from improprius "improper" (see improper). As "improper thing," 1670s.
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misbehavior (n.)

also misbehaviour, "improper, rude, or uncivil behavior," late 15c., from mis- (1) + behavior.

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uncomely (adj.)
c. 1200, "improper, unseemly, indecent," from un- (1) "not" + comely. Related: Uncomeliness.
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mismanagement 

"careless or improper management," 1660s; see mis- (1) "bad, wrong" + management.

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badness (n.)
"state of being evil, wrong, improper, deficient in quality, etc.," late 14c., baddenesse; see bad (adj.) + -ness.
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mispronunciation (n.)

"act of pronouncing incorrectly; a wrong or improper pronunciation," 1520s; see mis- (1) "bad, wrong" + pronunciation.

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abusive (adj.)
Origin and meaning of abusive

1530s (implied in abusively) "improper," from French abusif, from Latin abusivus "misapplied, improper," from abus-, past-participle stem of abuti "misuse," literally "use up" (see abuse (v.)). Meaning "full of abuse" is from 1580s. Shakespeare has abusious ("Taming of the Shrew," 1594). Abuseful "abounding in reproaches" was in use 17c.-19c. Related: Abusively; abusiveness.

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fistic (adj.)
"relating to or done with the fists," 1806, from fist (n.) + -ic. Long considered improper English ("Not in dignified use" - OED).
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maladministration (n.)

also mal-administration, "faulty or improper management of affairs, defective conduct in the administration of official duties," 1640s, from mal- + administration. Related: Maladminister (1705).

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