"confident of performance," by 1952, from expression can do "it is possible" (1903), literally "(I or we) can do (it)," which is perhaps based on earlier no can do (see no).

"to free from bias," 1708, from un- (2) "reverse, opposite of" + bias (v.).

The truest service a private man may hope to do his country is, by unbiassing his mind as much as possible. [Swift, "The Sentiments of a Church of England Man with respect to Religion and Government," 1708]

word-forming element meaning "wet, moist; moisture," from Greek hygros "wet, moist, fluid; weak, soft, flexible." Beekes says possible cognates include Old Norse vokr (accusative vokvan) "moist, wet;" Latin uvidus, udus.

curvature of the spine, 1704, Modern Latin, from Greek lordosis, from lordos "bent backwards," a word of uncertain origin, with possible cognates in Armenian, Celtic, and Germanic. From 1941 in reference to the mating position assumed by some female mammals. Related: Lordotic.

1794 "worst condition possible, point of greatest deterioration" (a sense now rare or obsolete), borrowed (by Coleridge) from French pessimisme, formed (on model of French optimisme) from Latin pessimus "worst," perhaps originally "bottom-most," from PIE *ped-samo-, suffixed (superlative) form of *ped- "to walk, stumble, impair," from root *ped- "foot." Compare Latin pessum "downward, to the ground."

As a name given to the metaphysical doctrines of Schopenhauer, Hartmann, etc., that this is the worst possible world, or that everything tends toward evil, it is recorded in English by 1835, from German pessimismus (Schopenhauer, 1819). As "tendency to exaggerate in thought the evils of life or to look only on the dark side," by 1815. The attempt to make a verb of it as pessimize (1862) did not succeed.

c. 1600, zerbet, "favorite cooling drink of the East," made from diluted fruit juice and sugar and cooled with fresh snow when possible, from Turkish serbet, from Persian sharbat, from Arabic sharba(t) "a drink," from shariba "he drank." Formerly also sherbert. Related to syrup, and compare sorbet.

"dejected, dispirited," 1580s, creast falne, it has the form of a past-participle adjective, but the verb crestfall is recorded only from 1610s, in reference to diseased horses, and is rare. It's possible that the image behind this use of the word is not having the crest fallen, as a defeated cock does, but horses. Crest-risen "proud, lusty" is from 1610s.

also cess-pool, "cistern or well to receive sediment or filth," 1670s, the first element perhaps an alteration of cistern, or perhaps a shortened form of recess [Klein]; or the whole may be an alteration of suspiral (c. 1400), "drainpipe," from Old French sospiral "a vent, air hole," from sospirer "breathe," from Latin suspirare "breathe deep" [Barnhart]. Meaning extended to "tank at the end of the pipe," which would account for a possible folk-etymology change in final syllable.

Other possible etymologies: Italian cesso "privy" [OED], from Latin secessus "place of retirement" (in Late Latin "privy, drain"); dialectal suspool, from suss, soss "puddle;" or cess "a bog on the banks of a tidal river."

"heel-bone," 1751, from Latin (os) calcaneum "bone of the heel," from calcem (nominative calx (1)) "heel," a word of uncertain origin, perhaps from Etruscan. De Vaan lists as possible cognates Old Prussian culczi "hip," Lithuanian kulkšnis "ankle-(bone)," Bulgarian kalka "hip, thigh." Related: Calcaneal.

early 15c., "unbelievable, surpassing belief as to what is possible," from Latin incredibilis "not to be believed, extraordinary," from in- "not" (see in- (1)) + credibilis "worthy of belief" (see credible). Used c. 1400 in a now-extinct sense of "unbelieving, incredulous." Related: Incredibly; incredibility.