scavengeryoudaoicibaDictYouDict[scavenger 词源字典]
scavenger: [15] A scavenger was originally a scavager – the extra n is the same as that intruded into messenger, passenger, etc. This was acquired from Anglo-Norman scawager, and it started life as a term for an official whose job was to collect taxes levied on foreign merchants. Etymologically it denoted ‘inspector’, for it was derived from the verb escauwer ‘inspect’, which was borrowed from Flemish scauwen ‘look at’, a relative of English show.

By the 16th century the scavenger had begun to come down in the world, first to a ‘street-cleaner’ and finally to ‘one who gathers or lives on what others have thrown away’. The verb scavenge was derived from it in the 17th century.

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forager (n.)youdaoicibaDictYouDict
late 14c., "a plunderer," from Old French foragier, from forrage "fodder; pillaging" (see forage (n.)). From early 15c. in English as "one who gathers food for horses and cattle."
glean (v.)youdaoicibaDictYouDict
early 14c., "to gather by acquisition, scrape together," especially grains left in the field after harvesting, but the earliest use in English is figurative, from Old French glener "to glean" (14c., Modern French glaner) "to glean," from Late Latin glennare "make a collection," of unknown origin. Perhaps from Gaulish (compare Old Irish do-glinn "he collects, gathers," Celtic glan "clean, pure"). Figurative sense was earlier in English than the literal one of "gather grain left by the reapers" (late 14c.). Related: Gleaned; gleaning.
guttersnipe (n.)youdaoicibaDictYouDict
also gutter-snipe, 1857, from gutter (n.) + snipe (n.); originally Wall Street slang for "streetcorner broker," attested later (1869) as "street urchin," also "one who gathers rags and paper from gutters." As a name for the common snipe, it dates from 1874 but is perhaps earlier.
ManhattanyoudaoicibaDictYouDict
main island of New York City, from Dutch, from a native name, perhaps representing a Delaware (Algonquian) source akin to Munsee munahan "island." Bright favors Munsee /e:nta menahahte:nk/ "where one gathers bows." As the name of a cocktail made of vermouth, whiskey, and a dash of bitters, it is attested from 1890 (in Manhattan cocktail).
nutter (n.)youdaoicibaDictYouDict
"one who gathers nuts," late 15c., from nut + -er (1). Meaning "crazy person" is British slang, 1958, from nut + -er (3). Nuttery "mental hospital" is attested from 1931; earlier it meant "place for storing nuts" (1881).