Etymology
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disloyalty (n.)

"want of loyalty, unfaithful behavior," early 15c., disloialte, from a variant of Old French desloiaute, desleauté "disloyalty, faithlessness, marital infidelity," from desloial, desleal "treacherous, false, deceitful" (Modern French déloyal), from des- "not, opposite of" (see dis-) + loial "of good quality; faithful; honorable; law-abiding; legitimate, born in wedlock," from Latin legalem, from lex "law" (see legal). Since c. 1600 especially "violation of allegiance or duty to a state or sovereign."

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disaffection (n.)

"alienation of affection, attachment, or good will; estrangement," especially "disloyalty to a government or existing authority," c. 1600; see dis- + affection. Perhaps from or based on French désaffection.

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impiety (n.)
mid-14c., from Old French impieté "impiety, wickedness" (12c.) or directly from Latin impietatem (nominative impietas) "irreverence, ungodliness; disloyalty, treason," noun of quality from impius "irreverent" (see impious).
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infidelity (n.)
c. 1400, "want of faith, unbelief in religion; false belief, paganism;" also (early 15c.) "unfaithfulness or disloyalty to a person" (originally to a sovereign, by 16c. to a lover or spouse), from French infidélité (12c.) or directly from Latin infidelitatem (nominative infidelitas) "unfaithfulness, faithlessness," noun of quality from infidelis "unfaithful, unbelieving" (see infidel).
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