O.E.
bisignisse (Northumbrian) "care, anxiety," from
bisig "careful, anxious, busy, occupied" (see
busy) +
-ness. Sense of "work, occupation" is first recorded 1387. Sense of "trade, commercial engagements" is first attested 1727. Modern two-syllable pronunciation is 17c.
Business card first attested 1840.