"diligence," early 15c., from Latin assiduitatem (nominative assiduitas) "continual presence," noun of quality from assiduus "continually present" (see assiduous).
Industry keeps at work, leaving no time idle. Assiduity (literally, a sitting down to work) sticks quietly to a particular task, with the determination to succeed in spite of its difficulty, or to get it done in spite of its length. Application, literally, bends itself to its work, and is, more specifically than assiduity, a steady concentration of one's powers of body and mind .... [Century Dictionary]
"dissolute loafer, tramp," 1864, American English, from bummer (q.v.) "loafer, idle person" (1855), which is probably from German. Bum first appears in a German-American context, and bummer was popular during the American Civil War in the slang of the North's army (which had as many as 216,000 German immigrants in the ranks). There may also be influence or merging with bum (n.1) "buttocks," which was applied insultingly to persons from 1530s and is in Jamieson's 1825 Scottish dictionary. Bum's rush "forcible ejection" first recorded 1910.
1733 (implied in palavering), "a long talk, a conference, a tedious discussion," sailors' slang, from Portuguese palavra "word, speech, talk," from a metathesis of Late Latin parabola "speech, discourse," from Latin parabola "comparison" (see parable). A doublet of parole.
In West Africa the Portuguese word became a traders' term for "negotiating with the natives," and apparently English picked up the word there. (The Spanish cognate, palabra, appears 16c.-17c. in Spanish phrases used in English.) The meaning "idle profuse talk" is recorded by 1748. The verb, "indulge in palaver," is by 1733, from the noun. Related: Palavering.
It forms all or part of: avoid; devastation; devoid; evacuate; evanescent; vacant; vacate; vacation; vacuity; vacuole; vacuous; vacuum; vain; vanish; vanity; vaunt; void; wane; want; wanton; waste.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit una- "deficient;" Avestan va- "lack," Persian vang "empty, poor;" Armenian unain "empty;" Latin vacare "to be empty," vastus "empty, waste," vanus "empty, void," figuratively "idle, fruitless;" Old English wanian "to lessen," wan "deficient;" Old Norse vanta "to lack."
late 14c., "careful attention to detail" (a sense now obsolete); also "skilled workmanship;" also "desire to know or learn, inquisitiveness" (in Middle English usually in bad senses: "prying; idle or vain interest in worldly affairs; sophistry; fastidiousness"); from Old French curiosete "curiosity, avidity, choosiness" (Modern French curiosité), from Latin curiositatem (nominative curiositas) "desire of knowledge, inquisitiveness," from curiosus "careful, diligent; inquiring eagerly, meddlesome," akin to cura "care" (see cure (n.)).
Neutral or good sense "desire to see or learn what is strange or unknown" is from early 17c. Meaning "an object of interest, something rare or strange" is from 1640s. Curiosity-shop is from 1818.
According to Kluge, the German word is from 17c., and its earliest sense is "oscillate back and forth." It is perhaps connected to words in German for "dangle" (baumeln), via "back-and-forth motion" of a bell clapper, transferred to "going back and forth," hence "doing nothing." Meaning "bad experience" is 1968 slang.