The Collaborative International Dictionary of English v.0.48:

Barter \Bar"ter\ (b[aum]r"t[~e]r), v. i. [imp. & p. p.
   Bartered (b[aum]r"t[~e]rd); p. pr. & vb. n. Bartering.]
   [OE. bartren, OF. barater, bareter, to cheat, exchange, perh.
   fr. Gr. pra`ttein to do, deal (well or ill), use practices or
   tricks, or perh. fr. Celtic; cf. Ir. brath treachery, W.
   brad. Cf. Barrator.]
   To traffic or trade, by exchanging one commodity for another,
   in distinction from a sale and purchase, in which money is
   paid for the commodities transferred; to truck.
   [1913 Webster]