needfire n.

Middle English nede, from Old English nied (West Saxon), ned (Mercian) "what is required, wanted, or desired; necessity, compulsion, the constraint of unavoidable circumstances; duty; hardship, emergency, trouble, time of peril or distress; errand, business," originally "violence, force," from Proto-Germanic *nauthiz/*naudiz (source also of Old Saxon nod, Old Norse nauðr "distress, emergency, need," Old Frisian ned, "force, violence; danger, anxiety, fear; need," Middle Dutch, Dutch nood "need, want, distress, peril," Old High German not, German Not "need, distress, necessity, hardship," Gothic nauþs "need").

This is apparently from a root *nauti- "death, to be exhausted," source also of Old English ne, neo, Old Norse na, Gothic naus "corpse;" Old Irish naunae "famine, shortage," Old Cornish naun "corpse;" Old Church Slavonic navi "corpse," nazda, Russian nuzda, Polish nędza "misery, distress;" Old Prussian nowis "corpse," nautin "need, distress," nawe "death;" Lithuanian novyti "to torture, kill," nove "death." As it is attested only in Germanic, Celtic, and Balto-Slavic, it might be non-PIE, from a regional substrate language.

From 12c. as "lack of something that is necessary or important; state or condition of needing something;" also "a necessary act, required work or duty." Meaning "extreme poverty, destitution, want of means of subsistence" is from early 14c. 

The more common Old English word for "need, necessity, want" was ðearf, but they were connected via a notion of "trouble, pain," and the two formed a compound, niedðearf "need, necessity, compulsion, thing needed." Nied also might have been influenced by Old English neod "desire, longing," which often was spelled the same. Nied was common in Old English compounds, such as niedfaru "compulsory journey," a euphemism for "death;" niedhæmed "rape" (the second element being an Old English word meaning "sexual intercourse");  niedling "slave."

Old English fyr "fire, a fire," from Proto-Germanic *fūr- (source also of Old Saxon fiur, Old Frisian fiur, Old Norse fürr, Middle Dutch and Dutch vuur, Old High German fiur, German Feuer "fire"), from PIE *perjos, from root *paewr- "fire." Current spelling is attested as early as 1200, but did not fully displace Middle English fier (preserved in fiery) until c. 1600.

PIE apparently had two roots for fire: *paewr- and *egni- (source of Latin ignis). The former was "inanimate," referring to fire as a substance, and the latter was "animate," referring to it as a living force (compare water (n.1)).

Brend child fuir fordredeþ ["The Proverbs of Hendyng," c. 1250]

English fire was applied to "ardent, burning" passions or feelings from mid-14c. Meaning "discharge of firearms, action of guns, etc." is from 1580s. To be on fire is from c. 1500 (in fire attested from c. 1400, as is on a flame "on fire"). To play with fire in the figurative sense "risk disaster, meddle carelessly or ignorantly with a dangerous matter" is by 1861, from the common warning to children. Phrase where's the fire?, said to one in an obvious hurry, is by 1917, American English.

Fire-bell is from 1620s; fire-alarm as a self-acting, mechanical device is from 1808 as a theoretical creation; practical versions began to appear in the early 1830s. Fire-escape (n.) is from 1788 (the original so-called was a sort of rope-ladder disguised as a small settee); fire-extinguisher is from 1826. A fire-bucket (1580s) carries water to a fire. Fire-house is from 1899; fire-hall from 1867, fire-station from 1828. Fire company "men for managing a fire-engine" is from 1744, American English. Fire brigade "firefighters organized in a body in a particular place" is from 1838. Fire department, usually a branch of local government, is from 1805. Fire-chief is from 1877; fire-ranger from 1887.

Symbolic fire and the sword is by c. 1600 (translating Latin flamma ferroque absumi); earlier yron and fyre (1560s), with suerd & flawme (mid-15c.), mid fure & mid here ("with fire and armed force"), c. 1200. Fire-breathing is from 1590s. To set the river on fire, "accomplish something surprising or remarkable" (usually with a negative and said of one considered foolish or incompetent) is by 1830, often with the name of a river, varying according to locality, but the original is set the Thames on fire (1796). The hypothetical feat was mentioned as the type of something impossibly difficult by 1720; it circulated as a theoretical possibility under some current models of chemistry c. 1792-95, which may have contributed to the rise of the expression.

[A]mong other fanciful modes of demonstrating the practicability of conducting the gas wherever it might be required, he anchored a small boat in the stream about 50 yards from the shore, to which he conveyed a pipe, having the end turned up so as to rise above the water, and forcing the gas through the pipe, lighted it just above the surface, observing to his friends "that he had now set the river on fire." ["On the Origins and Progress of Gas-lighting," in "Repertory of Patent Inventions," vol. III, London, 1827]