early 14c., present-participle adjective from will (v.1). Old English had -willendliche in compounds. Related: Willingly; willingness.
also largess, "willingness to give or spend freely; munificence," c. 1200, from Old French largesse, largece "a bounty, munificence," from Vulgar Latin *largitia "abundance" (source also of Spanish largueza, Italian larghezza), from Latin largus "abundant, large, liberal" (see large). In medieval theology, "the virtue whose opposite is avarice, and whose excess is prodigality" [The Middle English Compendium]. For Old French suffix -esse, compare fortress. Related: Largation.
early 15c., "gentleness, lightness," from Old French facilité "easiness, ease," from Latin facilitatem (nominative facilitas) "easiness, ease, fluency, willingness," from facilis "easy to do," from facere "to do" (from PIE root *dhe- "to set, put"). First in a medical book:
If it be nede forto smyte [the head] wiþ a malle, be it done with esynez or facilite [transl. Guy de Chauliac's "Grande Chirurgie"]
Its sense in English expanded to "opportunity" (1510s), to "aptitude, ease, quality of being easily done" (1530s). Meaning "place for doing something" which makes the word so beloved of journalists and fuzzy writers, first recorded 1872, via notion of "physical means by which (something) can be easily done."
climbing plant, Old English ifig, from West Germanic *ibakhs (source also of Middle Low German iflof, Dutch eiloof, Old High German ebahewi, German Efeu), a word of unknown origin; the second element in the Old High German word might be heu "hay."
Ivy bush as a sign of a tavern where wine is served is attested from mid-15c. (the ivy being sacred to Bacchus). Ivy League, inspired by the image of old, ivy-mantled walls, dates to 1935, originally in reference to a conference of football teams agreeing to organize teams and play games by set rules; it consists of Brown, Columbia, Cornell, Dartmouth, Harvard, Pennsylvania, Princeton, and Yale.
Incidentally, "Ivy League" is a poor name; it suggests that athletic morality is concentrated in a few very old colleges. Obviously, membership should be determined not by the amount of ivy on an institution's walls, but by its willingness to adopt and follow certain fundamental principles of education and sport. [Princeton Alumni Weekly, Dec. 6, 1935]
Old English habban "to own, possess; be subject to, experience," from Proto-Germanic *habejanan (source also of Old Norse hafa, Old Saxon hebbjan, Old Frisian habba, German haben, Gothic haban "to have"), from PIE root *kap- "to grasp." Not related to Latin habere, despite similarity in form and sense; the Latin cognate is capere "seize.
Sense of "possess, have at one's disposal" (I have a book) is a shift from older languages, where the thing possessed was made the subject and the possessor took the dative case (as in Latin est mihi liber "I have a book," literally "there is to me a book"). Used as an auxiliary in Old English, too (especially to form present perfect tense); the word has taken on more functions over time; Modern English he had better would have been Old English him (dative) wære betere.
To have to for "must" (1570s) is from sense of "possess as a duty or thing to be done" (Old English). Phrase have a nice day as a salutation after a commercial transaction attested by 1970, American English. Phrase have (noun), will (verb) is from 1954, originally from comedian Bob Hope, in the form Have tux, will travel; Hope described this as typical of vaudevillians' ads in Variety, indicating a willingness and readiness to perform anywhere.