scot-free adj.

"royal tax," a term that survived in old law and in scot-free; late Old English, "municipal charges and taxes," also "a royal tax or contribution sometimes levied for support of local officers." This is from Old Norse skot "contribution," etymologically "a shooting, shot; a thing shot, a missile" (from PIE root *skeud- "to shoot, chase, throw"). The Old Norse verb form, skjota, has a secondary sense of "transfer to another; pay." It is related to Old English sceotan "to pay, contribute," Middle English scotten "to bear one's share of;" Dutch schot, German Schoß "tax, contribution."

Also via Old French escot "reckoning, payment" (Modern French écot "share"), and via Medieval Latin scotum, scottum, both from Germanic, as is Spanish ecote. 

From c. 1300 as "payment for food or drink at a social gathering," also figurative (late 12c.), a sense also in the Old French word. Hence scot-ale (n.) "a drinking party, probably compulsory, held by a sheriff, forester, bailiff, etc., for which a contribution was exacted" [Middle English Compendium], attested from late 12c., with ending as in bridal. "Scot implies a contribution toward some object to which others contributed equally" [Century Dictionary].

Old English freo "exempt from; not in bondage, acting of one's own will," also "noble; joyful," from Proto-Germanic *friaz "beloved; not in bondage" (source also of Old Frisian fri, Old Saxon vri, Old High German vri, German frei, Dutch vrij, Gothic freis "free"), from PIE *priy-a- "dear, beloved," from root *pri- "to love."

The sense evolution from "to love" to "free" is perhaps from the terms "beloved" or "friend" being applied to the free members of one's clan (as opposed to slaves; compare Latin liberi, meaning both "free persons" and "children of a family"). For the older sense in Germanic, compare Gothic frijon "to love;" Old English freod "affection, friendship, peace," friga "love," friðu "peace;" Old Norse friðr "peace, personal security; love, friendship," German Friede "peace;" Old English freo "wife;" Old Norse Frigg, name of the wife of Odin, literally "beloved" or "loving;" Middle Low German vrien "to take to wife," Dutch vrijen, German freien "to woo."

Meaning "clear of obstruction" is from mid-13c.; sense of "unrestrained in movement" is from c. 1300; of animals, "loose, at liberty, wild," late 14c. Meaning "liberal, not parsimonious" is from c. 1300. Sense of "characterized by liberty of action or expression" is from 1630s; of art, etc., "not holding strictly to rule or form," from 1813. Of nations, "not subject to foreign rule or to despotism," recorded in English from late 14c. (Free world "non-communist nations" attested from 1950 on notion of "based on principles of civil liberty.") Sense of "given without cost" is 1580s, from notion of "free of cost."

Free even to the definition of freedom, "without any hindrance that does not arise out of his own constitution." [Emerson, "The American Scholar," 1837]

Free lunch, originally offered in bars to draw in customers, by 1850, American English. Free pass on railways, etc., attested by 1850. Free speech in Britain was used of a privilege in Parliament since the time of Henry VIII. In U.S., in reference to a civil right to expression, it became a prominent phrase in the debates over the Gag Rule (1836). Free enterprise recorded from 1832; free trade is from 1823; free market from 1630s. Free will is from early 13c. Free school is from late 15c. Free association in psychology is from 1899. Free love "sexual liberation" attested from 1822 (the doctrine itself is much older), American English. Free and easy "unrestrained" is from 1690s.