in reference to special court proceedings, late 13c., from Anglo-French lete, Anglo-Latin leta, of unknown origin; OED suggests possible connection to let (v.).
ASCII alternative alphabet used mostly in internet chat, by 1997, derived from elite (adj.), and sometimes the word also was used as an adjective in that sense in online gaming.
Entries linking to leet
Old English lætan (Northumbrian leta) "to allow; to leave behind, depart from; leave undone; bequeath," also "to rent, put to rent or hire" (class VII strong verb; past tense let, leort, past participle gelæten), from Proto-Germanic *letan (source also of Old Saxon latan, Old Frisian leta, Dutch laten, Old High German lazan, German lassen, Gothic letan "to leave, let"), from PIE *led-, extended form of root *lē- "to let go, slacken." If that derivation is correct, the etymological sense would be "let go through weariness, neglect."
"The shortening of the root vowel ... has not been satisfactorily explained" [OED]. Of blood, from late Old English. Other Old and Middle English senses include "regard as, consider; behave toward; allow to escape; pretend;" to let (someone) know and to let fly (arrows, etc.) preserve the otherwise obsolete sense of "to cause to." To let (someone) off "allow to go unpunished, excuse from service" is from 1814. To let on is from 1725 as "allow (something) to be known, betray one's knowledge of," 1822 as "pretend" (OED finds a similar use in the phrase never let it on him in a letter from 1637). To let out is late 12c. as "allow to depart" (transitive); intransitive use "be concluded," of schools, meetings, etc., is from 1888, considered by Century Dictionary (1895) to be "Rural, U.S." Of garments, etc., late 14c.
Let alone "abstain from interfering with" is in Old English; the phrase in the sense "not to mention, to say nothing of" is from 1812. To let (something) be "leave it alone" is from c. 1300; let it be "let it pass, leave it alone" is from early 14c. To let go is from c. 1300 as "allow to escape," 1520s as "cease to restrain," 1530s as "dismiss from one's thoughts." Let it go "let it pass, no matter" is as old as Chaucer's Wife of Bath: "But age allas Hath me biraft my beautee Lat it go, far wel, the deuel go ther with!" [c. 1395]. Let me see "show me" is from c. 1300.
"a choice or select body, the best part," 1823, from French élite "selection, choice," from Old French eslite (12c.), fem. past participle of elire, elisre "pick out, choose," from Latin eligere "choose" (see election). Borrowed in Middle English as "chosen person" (late 14c.), especially a bishop-elect, but it died out mid-15c. The word was re-introduced by Byron's "Don Juan." As an adjective by 1852. As a typeface, recorded by 1920.