late 12c., bileave, "confidence reposed in a person or thing; faith in a religion," replacing Old English geleafa "belief, faith," from West Germanic *ga-laubon "to hold dear, esteem, trust" (source also of Old Saxon gilobo, Middle Dutch gelove, Old High German giloubo, German Glaube), from *galaub- "dear, esteemed," from intensive prefix *ga- + PIE root *leubh- "to care, desire, love." The prefix in English was altered on analogy of the verb believe. The distinction of the final consonant from that of believe developed 15c.

The be-, which is not a natural prefix of nouns, was prefixed on the analogy of the vb. (where it is naturally an intensive) .... [OED]

The meaning "conviction of the truth of a proposition or alleged fact without knowledge" is by 1530s; it is also "sometimes used to include the absolute conviction or certainty which accompanies knowledge" [Century Dictionary]. From c. 1200 as "a creed, essential doctrines of a religion or church, things held to be true as a matter of religious doctrine;" the general sense of "that which is believed" is by 1714. Related: Beliefs.

Belief meant "trust in God," while faith meant "loyalty to a person based on promise or duty" (a sense preserved in keep one's faith, in good (or bad) faith, and in common usage of faithful, faithless, which contain no notion of divinity). But faith, as cognate of Latin fides, took on the religious sense beginning in 14c. translations, and belief had by 16c. become limited to "mental acceptance of something as true," from the religious use in the sense of "things held to be true as a matter of religious doctrine."

Middle English bileven, from Old English belyfan "to have faith or confidence" (in a person), earlier geleafa (Mercian), gelefa (Northumbrian), gelyfan (West Saxon), from Proto-Germanic *ga-laubjan "to believe," perhaps literally "hold dear (or valuable, or satisfactory), to love" (source also of Old Saxon gilobian "believe," Dutch geloven, Old High German gilouben, German glauben), ultimately a compound based on PIE root *leubh- "to care, desire, love" (see belief).

The meaning "be persuaded of the truth of" (a doctrine, system, religion, etc.) is from mid-13c.; the meaning "credit upon the grounds of authority or testimony without complete demonstration, accept as true" is from early 14c. The general sense of "be of the opinion, think" is from c. 1300. Related: Believed (formerly occasionally beleft); believing.

The form beleeve was common till 17c., the spelling then changed, perhaps by influence of relieve, etc. To believe on instead of in was more common in 16c. but now is a peculiarity of theology; believe of also sometimes was used in 17c. The expression believe it or not is attested by 1874; Robert Ripley's newspaper cartoon of the same name is from 1918. Emphatic you better believe attested from 1854.

1620s, vorloffe, "leave of absence," especially in military use, "leave or license given by a commanding officer to an officer or a soldier to be absent from service for a certain time," from Dutch verlof, literally "permission," from Middle Dutch ver- "completely, for" + laf, lof "permission," from Proto-Germanic *laubo-, from PIE root *leubh- "to care, desire, love." In English, the elements of it are for- + leave. The -gh spelling predominated from 1770s and represents the "f" that had been pronounced at the end of the word but later disappeared in English.

The spelling furloe occurs in the 18th century, but furlough appears to be the earliest spelling (as in Blount's Gloss., ed. 1674). As the spelling furlough does not follow that of the orig. language, it was prob. intended to be phonetic (from a military point of view), the gh perhaps as f and the accent on the second syllable .... [Century Dictionary]

By 1946 in reference to temporary layoffs of workers (originally of civilian employees in the U.S. military); by 1975 applied to conditional temporary releases of prisoners for the purpose of going to jobs (work-release).

"permission, liberty granted to do something," Old English leafe "leave, permission, licence," dative and accusative of leaf "permission," from Proto-Germanic *laubo (source also of Old Norse leyfi "permission," and, with prefix, Old Saxon orlof, Old Frisian orlof, German Urlaub "leave of absence"), from PIE root *leubh- "to care, desire, love," the original idea being "approval resulting from pleasure." It is a noun relative of lief "dear" (adj.); and compare belief. In the military sense, it is attested from 1771.

"sweetheart, paramour, loved one" (archaic), c. 1200, lemman, "loved one of the opposite sex; paramour, lover; wife;" also "a spiritually beloved one; redeemed soul, believer in Christ; female saint devoted to chastity; God, Christ, the Virgin Mary;" also a term of intimate address to a friend or lover, contracted from late Old English leofman, a compound of leof "dear" (see lief) + man "human being, person" (from PIE root *man- (1) "man").

Originally of either gender, though in deliberate archaic usage it tends to be limited to women. Often in religious use in early Middle English, of brides of Christ, the spiritually beloved of God, etc.; by c. 1300 it could mean "betrothed lover," and by late 14c. it had the pejorative sense "concubine, mistress, gallant." For loss of medial -f-, compare had.

"psychic drive or energy, usually associated with sexual instinct," 1892, carried over untranslated in English edition of Krafft-Ebing's "Psychopathia Sexualis"; and used in 1909 in A.A. Brill's translation of Freud's "Selected Papers on Hysteria" (Freud's use of the term led to its popularity); from Latin libido, lubido "desire, eagerness, longing; inordinate desire, sensual passion, lust," from libere "to be pleasing, to please," from PIE root *leubh- "to care, desire, love" (source also of love).

"dearly, gladly, willingly" (obsolete or archaic), c. 1250, from Middle English adjective lief "esteemed, beloved, dear," from Old English leof "dear, valued, beloved, pleasant" (also as a noun, "a beloved person, friend"), from Proto-Germanic *leuba- (source also of Old Norse ljutr, Old Frisian liaf, Dutch lief, Old High German liob, German lieb, Gothic liufs "dear, beloved"), from PIE root *leubh- "to care, desire, love."

Often with the dative and in personal constructions with have or would in expressions of choice or preference (and yet, to say the truth, I had as lief have the foppery of freedom, as the morality of imprisonment; "Measure for Measure"). I want and I'd love to are overworked and misused to fill the hole left in the language when I would lief faded in 17c.

also live-long, of a period of time, "long, whole" c. 1400, lefe longe (day or night), from leve, lief "dear" (see lief), used here as an emotional intensive + long (adj.). From late 16c. conformed in spelling and pronunciation to live (v.) as lief grew strange. German has cognate die liebe lange (Nacht), etc., literally "the dear long (night)."

Old English lufu "feeling of love; romantic sexual attraction; affection; friendliness; the love of God; Love as an abstraction or personification," from Proto-Germanic *lubo (source also of Old High German liubi "joy," German Liebe "love;" Old Norse, Old Frisian, Dutch lof; German Lob "praise;" Old Saxon liof, Old Frisian liaf, Dutch lief, Old High German liob, German lieb, Gothic liufs "dear, beloved"). The Germanic words are from PIE root *leubh- "to care, desire, love."

The weakened sense "liking, fondness" was in Old English. Meaning "a beloved person" is from early 13c. The sense "no score" (in tennis, etc.) is 1742, from the notion of playing for love (1670s), that is, for no stakes. Phrase for love or money "for anything" is attested from 1580s. The phrase no love lost (between two people) is ambiguous and was used 17c. in reference to two who love each other well (c. 1640) as well as two who have no liking for each other (1620s, the usual modern sense).

To fall in love is attested from early 15c.; to be in love with (someone) is from c. 1500. To make love is from 1570s in the sense "pay amorous attention to;" as a euphemism for "have sex," it is attested from c. 1950. Love affair "a particular experience of love" is from 1590s. Love life "one's collective amorous activities" is from 1919, originally a term in psychological jargon. Love beads is from 1968. Love bug, imaginary insect, is from 1883. Love-handles "the fat on one's sides" is by 1967.

"Even now," she thought, "almost no one remembers Esteban and Pepita but myself. Camilla alone remembers her Uncle Pio and her son; this woman, her mother. But soon we shall die and all memory of those five will have left the earth, and we ourselves shall be loved for a while and forgotten. But the love will have been enough; all those impulses of love return the love that made them. Even memory is not necessary for love. There is a land of the living and a land of the dead and the bridge is love, the only survival, the only meaning." [Thornton Wilder, "Bridge of San Luis Rey," 1927]

Old English luflic "affectionate, loving; loveable;" see love (n.) + -ly (1). Sense of "lovable on account of beauty, attractive" is from c. 1300; in modern use "applied indiscriminately to all pleasing material objects, from a piece of plum-cake to a Gothic cathedral" [George P. Marsh, "The Origin and History of the English Language," 1862]. As an expression of delight, 1610s.