busyyoudaoicibaDictYouDict[busy 词源字典]
busy: [OE] Busy goes back to an Old English bisig, which also meant ‘occupied’. Apart from Dutch bezig, it has no apparent relatives in any Indo-European language, and it is not known where it came from. The sense ‘inquisitive’, from which we get busybody [16], developed in the late 14th century. Business was originally simply a derivative formed from busy by adding the suffix -ness.

In Old English it meant ‘anxiety, uneasiness’, reflecting a sense not recorded for the adjective itself until the 14th century. The modern commercial sense seems to have originated in the 15th century. (The modern formation busyness, reflecting the fact that business can no longer be used simply for the ‘state of being busy’, is 19th-century.)
=> pidgin[busy etymology, busy origin, 英语词源]
busy (adj.)youdaoicibaDictYouDict
Old English bisig "careful, anxious," later "continually employed or occupied," cognate with Old Dutch bezich, Low German besig; 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" (preserved in busybody). The word was a euphemism for "sexually active" in 17c. Of telephone lines, 1893. Of display work, "excessively detailed, visually cluttered," 1903.
busy (v.)youdaoicibaDictYouDict
late Old English bisgian, from busy (adj.). Related: Busied; busying.