c.1200, "to entrap;" c.1300, "to set about (to do)," from under + take, v.. Similar formation in French entreprendre "to undertake," from entre "between, among" + prendre "to take." The under in this word may be the same one that also may form the first element of understand. Old English had underniman "to trap, accept" (cognate with Dutch ondernemen, German unternehmen).