"meddlesome person," 1520s, from busy (adj.) in the otherwise-obsolete sense "prying, meddlesome" + body "person."
Entries linking to busybody
busy adj.
Old English bisig "careful, anxious," later "continually employed or occupied, in constant or energetic action" cognate with Old Dutch bezich, Low German besig, but having no known connection with any other Germanic or Indo-European language. Still pronounced as in Middle English, but for some unclear reason the spelling shifted to -u- in 15c.
The notion of "anxiousness" has drained from the word since Middle English. Often in a bad sense in early Modern English, "prying, meddlesome, active in that which does not concern one" (preserved in busybody). The word was a euphemism for "sexually active" in 17c. Of telephone lines, 1884. Of display work, "excessively detailed, visually cluttered," 1903.
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.