cracker (n.2)youdaoicibaDictYouDict[cracker 词源字典]
Southern U.S. derogatory term for "poor, white trash" (1766), probably an agent noun from crack (v.) in the sense "to boast" (as in not what it's cracked up to be). Compare Latin crepare "to rattle, crack, creak," with a secondary figurative sense of "boast of, prattle, make ado about."
I should explain to your Lordship what is meant by crackers; a name they have got from being great boasters; they are a lawless set of rascalls on the frontiers of Virginia, Maryland, the Carolinas and Georgia, who often change their places of abode. [1766, G. Cochrane]
But DARE compares corn-cracker "poor white farmer" (1835, U.S. Midwest colloquial). Especially of Georgians by 1808, though often extended to residents of northern Florida. Another name in mid-19c. use was sand-hiller "poor white in Georgia or South Carolina."
Not very essentially different is the condition of a class of people living in the pine-barrens nearest the coast [of South Carolina], as described to me by a rice-planter. They seldom have any meat, he said, except they steal hogs, which belong to the planters, or their negroes, and their chief diet is rice and milk. "They are small, gaunt, and cadaverous, and their skin is just the color of the sand-hills they live on. They are quite incapable of applying themselves steadily to any labor, and their habits are very much like those of the old Indians." [Frederick Law Olmsted, "A Journey in the Seaboard Slave States," 1856]
[cracker etymology, cracker origin, 英语词源]
lap (n.)youdaoicibaDictYouDict
Old English læppa (plural læppan) "skirt or flap of a garment," from Proto-Germanic *lapp- (cognates: Old Frisian lappa, Old Saxon lappo, Middle Dutch lappe, Dutch lap, Old High German lappa, German Lappen "rag, shred," Old Norse leppr "patch, rag"), from PIE root *leb- "be loose, hang down."

Sense of "lower part of a shirt" led to that of "upper legs of seated person" (c. 1300). Used figuratively ("bosom, breast") from late 14c., as in lap of luxury, first recorded 1802. From 15c.-In 17c. the word (often in plural) was a euphemism for "female pudendum," but this is not the source of lap dance, which is first recorded 1993.
To lap dance, you undress, sit your client down, order him to stay still and fully clothed, then hover over him, making a motion that you have perfected by watching Mister Softee ice cream dispensers. [Anthony Lane, review of "Showgirls," "New Yorker," Oct. 16, 1995]
That this is pleasure and not torment for the client is something survivors of the late 20c. will have to explain to their youngers.
simplistic (adj.)youdaoicibaDictYouDict
"simple, plain, not compound," 1844, from simple (adj.) + -istic. From 1867 as "over-simple, trying to explain too much by a single principle." Also (1860) "of or pertaining to simples" (herbs used in healing, medicine of one ingredient only; the notion being that each herb possesses a particular virtue, thus a "simple" remedy), from simplist "one who studies simples" (1590s; see simple (adj.)) + -ic.