upstanding adj.

Old English up, uppe, from Proto-Germanic *upp- "up" (source also of Old Frisian, Old Saxon up "up, upward," Old Norse upp; Danish, Dutch op; Old High German uf, German auf "up"; Gothic iup "up, upward," uf "on, upon, under;" Old High German oba, German ob "over, above, on, upon"), from PIE root *upo "under," also "up from under," hence also "over."

As a preposition, "to a higher place" from c. 1500; also "along, through" (1510s), "toward" (1590s). Often used elliptically for go up, come up, rise up, etc. Up the river "in jail" first recorded 1891, originally in reference to Sing Sing, which is up the Hudson from New York City. To drive someone up the wall (1951) is from the notion of the behavior of lunatics or caged animals. Insulting retort up yours (scil. ass) is attested by late 19c.

Old English standan "occupy a place; stand firm; congeal; stay, continue, abide; be valid, be, exist, take place; oppose, resist attack; stand up, be on one's feet; consist, amount to" (class VI strong verb; past tense stod, past participle standen), from Proto-Germanic *standanan (source also of Old Norse standa, Old Saxon and Gothic standan, Old High German stantan, parallel with simpler forms, such as Swedish stå, Dutch staan, German stehen [see discussion in OED]), from *stathula, from PIE root *sta- "to stand, make or be firm."

Sense of "to exist, be present" is attested from c. 1300. Meaning "encounter without flinching" is from 1590s; weaker sense of "put up with" is from 1620s. Meaning "to submit" (to chances, etc.) is from c. 1700. Meaning "to pay for as a treat" is from 1821. Meaning "become a candidate for office" is from 1550s. Nautical sense of "hold a course at sea" is from 1620s. Meaning "to be so high when standing" is from 1831.

Stand back "keep (one's) distance" is from c. 1400. Phrase stand pat is from poker (1882), earlier simply stand (1824 in other card games). To stand down is from 1680s, originally of witnesses in court; in the military sense of "come off duty" it is first recorded 1916. To let (something) stand is from c. 1200. To stand for is c. 1300 as "count for;" early 14c. as "be considered in lieu of;" late 14c. as "represent by way of sign;" sense of "tolerate" first recorded 1620s. Phrase stands to reason (1620) is from earlier stands (is constant) with reason.

suffix used to form the present participles of verbs and the adjectives derived from them, from Old English present-participle suffix -ende, from PIE *-nt- (cognates: German -end, Gothic -and, Sanskrit -ant, Greek -on, Latin -ans, -ens). The vowel weakened in late Old English and the spelling with -g began 13c.-14c. among Anglo-Norman scribes who naturally confused it with -ing (1).