sunburn v.

Old English sunne "the sun," from Proto-Germanic *sunno (source also of Old Norse, Old Saxon, Old High German sunna, Middle Dutch sonne, Dutch zon, German Sonne, Gothic sunno "the sun"), from PIE *s(u)wen-, alternative form of root *sawel- "the sun."

Old English sunne was feminine (as generally in Germanic), and the fem. pronoun was used in English until 16c.; since then masc. has prevailed. The empire on which the sun never sets (1630) originally was the Spanish, later the British. To have one's place in the sun (1680s) is from Pascal's "Pensées"; the German imperial foreign policy sense (1897) is from a speech by von Bülow.

early 12c., brennen, "be on fire, be consumed by fire; be inflamed with passion or desire, be ardent; destroy (something) with fire, expose to the action of fire, roast, broil, toast; burn (something) in cooking," of objects, "to shine, glitter, sparkle, glow like fire;" chiefly from Old Norse brenna "to burn, light," and also from two originally distinct Old English verbs: bærnan "to kindle" (transitive) and beornan "be on fire" (intransitive).

All these are from Proto-Germanic *brennanan (causative *brannjanan),source also of Middle Dutch bernen, Dutch branden, Old High German brinnan, German brennen, Gothic -brannjan "to set on fire;" but the ultimate etymology is uncertain. Related: Burned/burnt (see -ed); burning.

Figurative use (of passions, battle, etc.) was in Old English. The meaning "be hot, radiate heat" is from late 13c. The meaning "produce a burning sensation, sting" is from late 14c. The sense of "cheat, swindle, victimize" is attested from 1650s. In late 18c, slang, burned meant "infected with venereal disease."

To burn one's bridges(behind one) "behave so as to destroy any chance of returning to a status quo" (attested by 1892 in Mark Twain), perhaps ultimately is from reckless cavalry raids in the American Civil War. Of money, to burn a hole in (one's) pocket "affect a person with a desire to spend" from 1850.

Slavic languages have historically used different and unrelated words for the transitive and intransitive senses of "set fire to"/"be on fire:" for example Polish palić/gorzeć, Russian žeč'/gorel.