Etymology
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immunity (n.)
late 14c., "exemption from service or obligation," from Old French immunité "privilege; immunity from attack, inviolability" (14c.) and directly from Latin immunitatem (nominative immunitas) "exemption from performing public service or charge, privilege," from immunis "exempt, free, not paying a share" (see immune (adj.)). Medical sense of "protection from disease" is from 1879, from French or German.
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immune (adj.)

mid-15c., "free, exempt" (from taxes, tithes, sin, etc.), from Latin immunis "exempt from public service, untaxed; unburdened, not tributary," literally "not paying a share," from assimilated form of in- "not, opposite of" (see in- (1)) + munis "performing services" (compare municipal), from PIE *moi-n-es-, suffixed form of root *mei- (1) "to change, go, move." Specific modern medical sense of "exempt (from a disease)," typically because of inoculation, is from 1881, a back-formation from immunity. Immune system attested by 1917.

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vaccinate (v.)
1803, "to inoculate with a vaccine," originally with cowpox for the purpose of procuring immunity from smallpox, back-formation from vaccination. Related: Vaccinated; vaccinating.
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cow-pox (n.)

also cowpox, disease of cattle, 1780, see cow (n.) + pox. The fluid of the vesicles can communicate it to humans, and getting it provides almost complete immunity to smallpox.

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autoimmune (adj.)

also auto-immune, "arising from an abnormal immune response to a normal body part," 1952, from auto- + immune. Related: Autoimmunity, attested by 1903 as "immunity, natural or acquired, effected by the unaided powers of the organism, independent of external agencies." Modern sense of "immune responses of an organism against its own healthy cells and tissues" is from 1950s.

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inviolable (adj.)
mid-15c., "that is to be kept without violation" (of an oath, etc.), from Latin inviolabilis "inviolable, invulnerable," from in- "not, opposite of" (see in- (1)) + violabilis "that may be injured, easily wounded," from violare "to do violence to" (see violation). Meaning "having a right or guaranty of immunity" (of a place of sanctuary, etc.) is from 1570s. Meaning "incapable of being injured" is from 1520s. Related: Inviolably.
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exemption (n.)

c. 1400, exempcioun, "immunity from a law or statute, state of being free from some undesirable requirement," from Old French exemption, exencion or directly from Latin exemptionem (nominative exemptio) "a taking out, removing," noun of action from past-participle stem of eximere "remove, take out, take away; free, release, deliver, make an exception of," from ex "out" (see ex-) + emere "buy," originally "take," from PIE root *em- "to take, distribute." 

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privilege (n.)

mid-12c. "grant, commission" (recorded earlier in Old English, but as a Latin word), from Old French privilege "right, priority, privilege" (12c.) and directly from Latin privilegium "law applying to one person, bill of law in favor of or against an individual;" in the post-Augustine period "an ordinance in favor of an individual" (typically the exemption of one individual from the operation of a law), "privilege, prerogative," from privus "individual" (see private (adj.)) + lex (genitive legis) "law" (see legal (adj.)).

From c. 1200 as "power or prerogative associated with a certain social or religious position." Meaning "advantage granted, special right or favor granted to a person or group, a right, immunity, benefit, or advantage enjoyed by a person or body of persons beyond the common advantages of other individuals" is from mid-14c. in English. From late 14c. as "legal immunity or exemption."

Formerly of such things as an exemption or license granted by the Pope, or special immunity or advantage (as freedom of speech) granted to persons in authority or in office; in modern times, with general equality of all under the law, it is used of the basic rights common to all citizens (habeas corpus, voting, etc.).

Privilege is also more loosely used for any special advantage: as, the privilege of intimacy with people of noble character. Prerogative is a right of precedence, an exclusive privilege, an official right, a right indefeasible on account of one's character or position : as, the Stuart kings were continually asserting the royal prerogative, but parliament resisted any infringement upon its privileges. [Century Dictionary]

Middle English also had pravilege "an evil law or privilege" (late 14c.), from Medieval Latin pravilegium, a play on privilegium by substitution of pravus "wrong, bad."

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inoculate (v.)
mid-15c., "implant a bud into a plant," from Latin inoculatus, past participle of inoculare "graft in, implant a bud or eye of one plant into another," from in- "in" (from PIE root *en "in") + oculus "bud," originally "eye" (from PIE root *okw- "to see"). Meaning "implant germs of a disease to produce immunity" is from inoculation, originally in reference to smallpox, after 1799, often used in sense of "to inoculate with a vaccine." Related: Inoculated; inoculating.
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sanctuary (n.)

early 14c., seintuarie, sentwary, etc., "consecrated place, building set apart for holy worship; holy or sacred object," from Anglo-French sentuarie, Old French saintuaire "sacred relic, holy thing; reliquary, sanctuary," from Late Latin sanctuarium "a sacred place, shrine" (especially the Hebrew Holy of Holies in the temple in Jerusalem; see sanctum), also "a private room;" in Medieval Latin also "a church, cemetery; right of asylum," from Latin sanctus "holy" (see saint (n.)). 

Since the time of Constantine and by medieval Church law, fugitives or debtors enjoyed immunity from arrest and ordinary operations of the law in certain churches, hence its use by mid-14. of churches or other holy places with a view to their inviolability. The transferred sense of "immunity from punishment by virtue of having taken refuge in a church or similar building" is by early 15c., also of the right to such. (Exceptions were made in England in cases of treason and sacrilege.)

The general (non-ecclesiastical) sense of "place of refuge or protection" is attested from 1560s; as "land set aside for wild plants or animals to breed and live" it is recorded by 1879 in reference to the American bison.

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