mid-15c. (implied in tauntingly), possibly [Skeat] from Middle French tanter, tenter "to tempt, try, provoke," variant of tempter "to try" (see tempt). Or from Middle French tant pour tant "so much for so much, tit for tat," on notion of "sarcastic rejoinder" (considered by OED the "most likely suggestion"). Related: Taunted; taunting.
1520s, "bitter invective," probably from taunt (v.).