c. 1300, ani-bodi, "any person," from any + body. One-word form attested by 1826. Phrase anybody's game (or race, etc.) is from 1840.
Entries linking to anybody
any adj., pron.
"one, a or an, some," Old English ænig (adjective, pronoun) "any, anyone," literally "one-y," from Proto-Germanic *ainagas (source also of Old Saxon enig, Old Norse einigr, Old Frisian enich, Dutch enig, German einig), from PIE root *oi-no- "one, unique." The -y may have diminutive force here.
As a noun, late 12c.; as an adverb, "in any degree," c. 1400. Emphatic form any old______ (British variant: any bloody ______) is recorded from 1896. At any rate is recorded from 1847. Among the large family of compounds beginning with any-, anykyn "any kind" (c. 1300) did not survive, and Anywhen (1831) is rarely used, but OED calls it "common in Southern [English] dialects."
[A]ani refers to single entities, amounts, etc., occurring at random or chosen at random, as being convenient, suitable, to one's liking, etc. It is frequently emphatic and generalizing, having the force of 'any whatever, any at all' and 'any and every'. It is common in questions, conditional clauses, and negative statements, but not in affirmative statements (where som is used instead). [The Middle English Compendium]
body n.
Middle English bodi, from Old English bodig "trunk of a man or beast; the whole physical structure of a human or animal; material frame, material existence of a human; main or principal part of anything," related to Old High German botah, but otherwise of unknown origin. Not elsewhere in Germanic, and the word has died out in German (replaced by Leib, originally "life," and Körper, from Latin), "but in English body remains as a great and important word" [OED].
The extension to "a person, a human being" is by c. 1300. The meaning "main part" of anything was in late Old English, hence its use in reference to vehicles (1520s). From 1580s as "part of the dress which covers the body."
It is attested from 1590s as "main part of a group, any number of individuals spoken of collectively" and from 1660s as "main portion of a document." Contrasted with soul at least since mid-13c. The meaning "corpse" ("dead body") is from c. 1200. The word was transferred to matter generally in Middle English (as in heavenly body, late 14c.).
Body politic "the nation, the state, whole body of people living under an organized government" is recorded from late 15c., with French word order. Body image was coined 1934. Body count "number of enemy killed in battle or otherwise" is from 1968, from the Vietnam War. Body language is attested from 1967, perhaps from French langage corporel (1966). Body-snatcher "one who secretly disinters the bodies of the recently dead for dissection" is from 1834. Defiant phrase over my dead body attested by 1833.
anyone n.
"any person or persons," 1844 as one word; since Old English as two words, from any + one. Old English also used ænigmon in this sense, Middle English eani mon, ani on; also compare anybody.