late Old English, verbal noun from spend (v.). Spending-money is from 1590s.

mid-15c., "the spending of money," from Middle English emploien (see employ) + -ment. From 1590s as "an errand or commission;" 1640s as "a person's regular occupation or business."

"a spending of a night in a place other than one's residence," 1935, from the verbal phrase; see sleep (v.) + over (adv.). Earlier the verbal phrase meant "sleep late, oversleep" (1827).

1828, "ostentatious display," American English, of uncertain origin; originally among the class of words considered characteristic of "Western" (i.e. Kentucky) dialect. Perhaps a blend of splash and surge. The meaning "extravagant indulgence in spending" is first recorded 1928.

"spending or bestowing profusely," mid-15c., laves, from Old French lavasse,lavache (n.) "a torrent of rain, deluge" (15c.), from laver "to wash," from Latin lavare "to wash" (from PIE root *leue- "to wash"). Related: Lavishly; lavishness.

1640s, "an extravagant act," from French extravagance, from Late Latin extravagantem (see extravagant). Specifically of wasteful spending from 1727. Meaning "quality of being extravagant" is from 1670s. Extravagancy, "a wandering," especially "a wandering from the usual course," is attested from c. 1600, now rare.

mid-15c., "spending or contributing freely," from Old French distributif and directly from Late Latin distributivus, from Latin distribut-, past-participle stem of distribuere "to divide, deal out in portions" (see distribute). Meaning "that distributes" is from 1510s. In logic, "showing that a statement refers to each individual of a class separately," 1725 (opposed to collective). Related: Distributively.

1772, from tea + party (n.). Political references to tea party all trace to the Boston tea party of 1773 (the name seems to date from 1824), in which radicals in Massachusetts colony boarded British ships carrying tea and threw the product into Boston Harbor in protest against the home government's taxation policies. It has been a model for libertarian political actions in the U.S. (generally symbolic), including citizen gatherings begun in early 2009 to protest government spending.

by 1996, from metropolitan + -sexual, ending abstracted from homosexual, heterosexual. Wikipedia defines it as "a portmanteau of metropolitan and heterosexual, coined in 1994 describing a man who is especially meticulous about his grooming and appearance, typically spending a significant amount of time and money on shopping as part of this."

Nevertheless, the metrosexual man contradicts the basic premise of traditional heterosexuality—that only women are looked at and only men do the looking. Metrosexual man might prefer women, he might prefer men, but when all's said and done nothing comes between him and his reflection. [Mark Simpson, "It's a Queer World," 1996]

also formerly expence, late 14c., "action of spending or giving away, a laying out or expending," also "funds provided for expenses, expense money; damage or loss from any cause," from Anglo-French expense, Old French espense "money provided for expenses," from Late Latin expensa "disbursement, outlay, expense," noun use of neuter plural past participle of Latin expendere "weigh out money, pay down," from ex "out, out of" (see ex-) + pendere "to hang, cause to hang; weigh; pay" (from PIE root *(s)pen- "to draw, stretch, spin"). For the financial sense of the Latin verb, see pound (n.1). 

Latin spensa also yielded Medieval Latin spe(n)sa, the sense of which specialized to "outlay for provisions," then "provisions, food" before it was borrowed into Old High German as spisa and became the root of German Speise "food," now mostly meaning prepared food, and speisen "to eat." Expense account is from 1872.