affect (v.2)youdaoicibaDictYouDict
"to make a pretense of," 1660s, earlier "to assume the character of (someone)," 1590s; originally in English "to aim at, aspire to, desire" (early 15c.), from Middle French affecter (15c.), from Latin affectare "to strive after, aim at," frequentative of afficere (past participle affectus) "to do something to, act on" (see affect (n.)). Related: Affected; affecting.
bead (n.)youdaoicibaDictYouDict
mid-14c., bede "prayer bead," from Old English gebed "prayer," with intensive or collective prefix *ge- + Proto-Germanic *bidam "entreaty" (cognates: Middle Dutch bede, Old High German beta, German bitte, Gothic bida "prayer, request"), from PIE *gwhedh- "to ask, pray."

Shift in meaning came via beads threaded on a string to count prayers, and in phrases like to bid one's beads, to count one's beads. German cognate Bitte is the usual word for conversational request "please." Also related to bid (Old English biddan) and Gothic bidjan "to ask, pray." Sense transferred to "drop of liquid" 1590s; to "small knob forming front sight of a gun" 1831 (Kentucky slang); hence draw a bead on "take aim at," 1841, U.S. colloquial.
guess (v.)youdaoicibaDictYouDict
c. 1300, gessen "to infer from observation, perceive, find out; form an opinion, judge, decide, discern; evaluate, estimate the number, importance, etc. of," perhaps from Scandinavian (compare Middle Danish gitse, getze "to guess," Old Norse geta "guess, get"), or from or influenced by Middle Dutch gessen, Middle Low German gissen "to guess," all from Proto-Germanic *getan "to get" (see get (v.)). The prehistoric sense evolution then would be from "get," to "take aim at," to "to estimate." Meaning "to hit upon the right answer" is from 1540s. Spelling with gu- is late 16c., sometimes attributed to Caxton and his early experience as a printer in Bruges. Related: Guessed; guessing. Guessing game attested from 1650s. To keep (someone) guessing "keep him in a state of suspense" is from 1896, American English.
[T]he legitimate, English sense of this word is to conjecture; but with us, and especially in New England, it is constantly used in common conversation instead of to believe, to suppose, to think, to imagine, to fancy. [Bartlett, "Dictionary of Americanisms," 1848]
perpetual (adj.)youdaoicibaDictYouDict
mid-14c., from Old French perpetuel "without end" (12c.) and directly from Latin perpetualis "universal," in Medieval Latin "permanent," from perpetuus "continuous, universal," from perpetis, genitive of Old Latin perpes "lasting," probably from per- "through" + root of petere "to seek, go to, aim at" (see petition (n.)). Related: Perpetually. Perpetual motion is attested from 1590s.
purchase (v.)youdaoicibaDictYouDict
c. 1300, "acquire, obtain; get, receive; procure, provide," also "accomplish or bring about; instigate; cause, contrive, plot; recruit, hire," from Anglo-French purchaser "go after," Old French porchacier "search for, procure; purchase; aim at, strive for, pursue eagerly" (11c., Modern French pourchasser), from pur- "forth" (possibly used here as an intensive prefix; see pur-) + Old French chacier "run after, to hunt, chase" (see chase (v.)).

Originally to obtain or receive as due in any way, including through merit or suffering; specific sense of "acquire for money, pay money for, buy" is from mid-14c., though the word continued to be used for "to get by conquest in war, obtain as booty" up to 17c. Related: Purchased; purchasing.
stochastic (adj.)youdaoicibaDictYouDict
1660s, "pertaining to conjecture," from Greek stokhastikos "able to guess, conjecturing," from stokhazesthai "to guess, aim at, conjecture," from stokhos "a guess, aim, target, mark," literally "pointed stick set up for archers to shoot at," from PIE *stogh-, variant of root *stegh- "to stick, prick; pointed" (see sting (v.)). The sense of "randomly determined" is from 1934, from German stochastik (1917).
till (v.)youdaoicibaDictYouDict
"cultivate (land)" early 13c.; "plow," late 14c., from Old English tilian "cultivate, tend, work at, get by labor," originally "strive after, aim at, aspire to," related to till "fixed point, goal," and til "good, useful, suitable," from Proto-Germanic *tilojan (cognates: Old Frisian tilia "to get, cultivate," Old Saxon tilian "to obtain," Middle Dutch, Dutch telen "to breed, raise, cultivate, cause," Old High German zilon "to strive," German zielen "to aim, strive"), from source of till (prep.).

For sense development, compare expression work the land, Old Norse yrkja "work," but especially "cultivate" (and also "to make verses"); Old Church Slavonic delati "work," also "cultivate." Related: Tilled; tilling.