Online Etymology Dictionary

furtive (adj.): late 15c. (implied in furtively), from French furtif, from Latin furtivus "stolen, hidden, secret," from furtum "theft, robbery," from fur (genitive furis) "thief," probably from PIE *bhor-, from root *bher- (1) "to carry" (see infer). Related: Furtiveness.
furtively (adv.): late 15c.; from furtive + -ly (2).
furuncle (n.): "a boil," 1670s, from Latin furunculus, "a boil," literally "little thief," diminutive of fur "thief." Related: Furuncular; furunculous.
fury (n.): late 14c., "fierce passion," from Old French furie (14c.), from Latin furia "violent passion, rage, madness," related to furere "to rage, be mad." Romans used Furiæ to translate Greek Erinyes, the collective name for the avenging deities sent from Tartarus to punish criminals (in later accounts three in number and female). Hence, figuratively, "an angry woman" (late 14c.).
furze (n.): "evergreen shrub," Old English fyrs, of unknown origin, with no known connections.
fuscous (adj.): "dark-colored," 1660s, from Latin fuscus "dark, swarthy" (see dusk).
fuse (v.): 1680s, "to melt" (transitive), back-formation from fusion. Intransitive sense, "to become liquid," attested from 1800. Figurative sense of "blend different things" is first recorded 1817. Related: Fused; fusing.
fuse (n.): "combustible cord or tube for lighting an explosive device," also fuze, 1640s, from Italian fuso "spindle" (so called because the originals were long, thin tubes filled with gunpowder), from Latin fusus "spindle," of uncertain origin. Influenced by French fusée "spindleful of hemp fiber," and obsolete English fusee "musket fired by a fuse." Meaning "device that breaks an electrical circuit" first recorded 1884, so named for its shape, but erroneously attributed to fuse (v.) because it melts.
fusee (n.): also fuzee, type of light musket, 1660s, from French fusil (see fusilier).
fuselage (n.): 1909, from French fuselage, from fuselé "spindle-shaped," from Old French *fus "spindle," from Latin fusus "spindle" (see fuse (n.)). So called from its shape.
fusible (adj.): late 14c., from Old French fusible, from Medieval Latin fusibilis, from Latin fus-, stem of fundere "pour, melt" (see found (v.2)).
fusiform (adj.): "spindle-shaped," 1746, from Latin fusus "spindle" (see fuse (n.)) + -form.
fusil (n.): flintlock musket, 1670s, from French fusil (see fusilier).
fusilier (n.): 1670s, "soldier armed with a musket," from French fusilier, from Old French fusil "musket," earlier "steel for a tinderbox," from Vulgar Latin *focilis (petra) "(stone) producing fire," from Latin focus "hearth," in Vulgar Latin "fire" (see focus (n.)). Retained by certain regiments of the British army that were formerly armed with fusils.
fusillade (n.): "simultaneous discharge of firearms," 1801, from French fusillade, from fusiller "to shoot," from fusil "musket" (see fusilier). As a verb from 1816.
fusion (n.): 1550s, from Middle French fusion, from Latin fusionem (nominative fusio) "an outpouring, effusion," noun of action from fusus, past participle of fundere "pour, melt" (see found (v.2)). In nuclear physics sense, first recorded 1947; in jazz sense, by 1972.
fuss (n.): 1701, perhaps an alteration of force, or imitative of bubbling or sputtering sounds, or from Danish fjas "foolery, nonsense." First attested in Anglo-Irish writers, but no obvious connections to Irish. To make a fuss was earlier to keep a fuss (1726).
fuss (v.): 1792, from fuss (n.). Related: Fussed; fussing.
fussbudget (n.): 1904, from fuss (n.) + budget (n.). One of several similar formulations around this time: Cf. fussbox (1901); fusspot (1921).
fussy (adj.): 1831, from fuss (n.) + -y (2). Related: Fussily; fussiness.
fustian (n.): "thick cotton cloth," c.1200, from Old French fustaigne, from Medieval Latin fustaneum, probably from Latin fustis "staff, stick of wood," probably a loan-translation of Greek xylina lina "linens of wood" (i.e. "cotton"), but the Medieval Latin word also is sometimes said to be from Fostat, town near Cairo where this cloth was manufactured. [Klein finds this derivation untenable.] Figurative sense of "pompous, inflated language" recorded by 1590s.
fusty (adj.): "stale-smelling," late 14c., from Old French fusté "fusty, tasting of the cask," from Old French fuist "wine cask," originally "stick, stave," from Latin fustis "staff, stick of wood." Related: Fustiness.
futhorc (n.): 1851, historians' name for the Germanic runic alphabet; so called from its first six letters, on the model of alphabet.
futile (adj.): 1550s, from Middle French futile, from Latin futilis "vain, worthless, futile," literally "pouring out easily" (of a vessel), hence "easily emptied, leaky, unreliable," from base of fundere "pour, melt," from PIE root *gheu- "to pour" (see found (v.2)). Related: Futilely.
futility (n.): 1620s, from French futilité or directly from Latin futilitatem (nominative futilitas) "worthlessness," from futilis (see futile). Hence, jocular futilitarian (1827).
futon (n.): 1876, from Japanese, said to mean "bedroll" or "place to rest."
future (adj.): late 14c., from Old French futur, from Latin futurus "going to be, yet to be," as a noun, "the future," irregular suppletive future participle of esse "to be," from PIE *bheue- (see be). The English noun (late 14c.) is modeled on Latin futura, neuter plural of futurus.
futures (n.): "goods sold on agreement for future delivery," 1880; see future.
futurism (n.): 1909, from Italian futurismo, coined 1909 by Italian poet Filippo Tommaso Marinetti (1876-1944); see future + -ism. Futurist is attested from 1842, originally theological.
futuristic (adj.): 1915, "avant garde," from futurism. Meaning "pertaining to the future" is from 1958, from future + -istic.
futurity (n.): c.1600, from future + -ity.
futurology (n.): 1946, from future + -ology.
futz (v.): "loaf, waste time," 1932, American English, perhaps from Yiddish. Related: Futzed; futzing.
fuze (n.): see fuse (n.).
fuzz (n.): 1590s, fusse, first attested in fusball "puff ball of tiny spores," of uncertain origin. Meaning "the police" is American English, 1929, underworld slang, origin and connection to the older word unknown. Perhaps a variant of fuss, with a notion of "hard to please."
fuzzy (adj.): 1610s, "soft, spongy," from fuzz + -y (2). Cf. Low German fussig "weak, loose, spongy," Dutch voos "spongy." From 1713 as "covered with fuzz;" 1778 as "blurred;" and 1937 as "imprecise," with reference to thought, etc. Related: Fuzzily; fuzziness.
fylfot (n.): supposedly a native name for the swastika (used as a decorative device), but only attested in a single, damaged c.1500 manuscript, and there it may refer to any sort of device used to fill the bottom (foot) of a design. "[I]t is even possible that it may have been a mere nonce-word" [OED].