1530s, “a hanger-on, a toady, person who lives on others,” from French parasite (16c.) or directly from Latin parasitus “toady, sponger,” and directly from Greek parasitos “one who lives at another’s expense, person who eats at the table of another,” especially one who frequents the tables of the rich and earns his welcome by flattery.
This is from noun use of an adjective meaning “feeding beside,” from para- “beside” (see para- (1)) + sitos “grain, bread, food,” a word of unknown origin. It is in other Greek compounds, such as syssitos “table companion, messmate.” Often explained as a loan-word from another IE language or as a substrate word, but Beekes suggests it is from an IE root for “to strike, hit,” and related to simos “snub-nosed” (“flattened”).
The scientific meaning “animal or plant that lives on or in and at the expense of another” is recorded from 1640s (implied in parasitical).
There is scarcely any animal that may not or does not serve as the host of parasites, and some parasites are themselves the hosts of other parasites. … Parasites form no technical group of animals, since representatives of almost any class or order, from protozoans to vertebrates, may be parasitic. Most of the leading divisions of animals, however, include some members, whether genera, families, orders, or even classes, whose habit is extensively or exclusively parasitic. [Century Dictionary]
in zoology, “infest as a parasite,” 1880, from parasite + -ize. Related: Parasitized; parasitizing.
“of pertaining to, or characteristic of a parasite,” in any sense, 1620s, from Latin parasiticus, from Greek parasitikos “of or pertaining to a parasite; the trade of a parasite,” from parasitos “one who lives at another’s expense” (see parasite). Biological sense is from 1731. Related: Parasitical, 1570s in reference to toadies; from 1640s in the biological sense.
“a habitual living on or at the expense of another,” 1610s, from parasite + -ism. Biological sense of “vital relation of a parasite to a host” is by 1840.
also super-parasite, 1891, “a parasite of a parasite;” see super- + parasite (n.). Related: Superparasitic (1877); superparasitism.
“parasite of the genus Schistosoma” (1905); the genus name (1858) is a Modern Latin formation from Greek skhistos “divided, cloven” (from skhizein “to split;” see schizo-) + sōma “body” (see somato-). Related: Schistosomatosis “disease caused by schistosomes” (1906).
“association between organisms in which one is carried on the body of another but is not a parasite,” 1914, from French phorésie (1896), from Greek phorēsis “being carried,” from pherein “to carry,” from PIE root *bher- (1) “to carry,” also “to bear children.”
also pick-thank, c. 1500, “an officious fellow who does what he is not asked to do for the sake of gaining favor, a parasite or toady,” from phrase pick thanks “procure consideration or favor by servile or underhanded means” (early 15c.); see pick (v.) + thanks.
Middle English sothen, from Old English soðian “show to be true, bear witness, offer confirmation” (senses now obsolete), from soð “true” (see sooth). The sense of “quiet, comfort, restore to tranquility,” in reference to a person or animal, is by 1690s, via the notion of “to assuage one by asserting that what he says is true,” a sense attested from 1560s (and compare Old English gesoð “a parasite, flatterer”). The meaning “reduce the intensity” (of a pain, etc.) is from 1711. Related: Soothed; soother; soothing.
1630s, “to practice fraud or trickery, live by one’s wits,” also a noun (1630s) “a needy, disreputable parasite” [OED], of uncertain origin. Perhaps from German schurke “scoundrel, rogue, knave, villain” (see shark (n.)).
Both older senses are obsolete. The meaning “go evasively or slyly, slink, sneak away” is from 1580s; hence that of “evade one’s work or duty,” recorded by 1785, originally slang or colloquial. It also was used by 1787 in the sense of “evade (someone), avoid meeting, dodge.” Related: Shirked; shirking.
Source: O
https://www.etymonline.com
oxford dictionary