c. 1400, robous, "waste, broken, or worn-out material," especially "rubble from the demolition of a building, etc.," from Anglo-French rubouses (late 14c.), a word of unknown origin. There are said to be no apparent cognates in Old French; OED says "app. related in some way to rubble."
The spelling with -ish is from late 15c. As "any useless or worthless stuff" by c. 1600. The verb sense of "disparage, criticize harshly" is attested by 1953 in Australian and New Zealand slang. Related: Rubbished; rubbishing.
"rough, irregular stones broken from larger masses," especially "waste fragments from the demolition of a building, etc.," late 14c., robeyl, from Anglo-French *robel "bits of broken stone," which is of obscure origin, apparently related to rubbish "waste fragments" [OED], but also possibly from Old French robe (see rob). Middle English Compendium compares Anglo-Latin rubisum, robusium.
"accumulation of loose matter or rubbish from some destructive operation or process," 1708, from French débris "remains, waste, rubbish" (16c.), from obsolete debriser "break down, crush," from Old French de- (see de-) + briser "to break," from Late Latin brisare, which is possibly of Gaulish origin (compare Old Irish brissim "I break").
early 15c., "the formal enumerating of the votes in an election to an office or dignity" (according to OED, "Now chiefly in Canon Law"), from Late Latin scrutinium "a search, inquiry" (in Medieval Latin, "a mode of election by ballot"), from Latin scrutari "to examine, investigate, search" (from PIE root *skreu- "to cut; cutting tool;" see shred (n.)). The meaning "close investigation or examination" is recorded from c. 1600.
Perhaps the original notion of the Latin word is "to search among rubbish," via scruta (plural) "trash, rags, rubbish" ("shreds"); or the original sense might be "to cut into, scratch."
1640s, transitive, "cleanse from filth," a back-formation from scavenger (q.v.). The intransitive meaning "search through rubbish" for usable food or objects is suggested by 1880s; the transitive sense of "extract and collect anything usable from discarded material" is by 1922. Related: Scavenged; scavenging.