What's the difference between barter and swop?

Barter

Definition:

(v. i.) 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.
(v. t.) To trade or exchange in the way of barter; to exchange (frequently for an unworthy consideration); to traffic; to truck; -- sometimes followed by away; as, to barter away goods or honor.
(n.) The act or practice of trafficking by exchange of commodities; an exchange of goods.
(n.) The thing given in exchange.

Example Sentences:

(1) Children with living parents were bartered, abducted and palmed off to Americans and northern Europeans who paid large sums to have a child of their own.
(2) It is a bit rich to expect us to state exactly how we’ll whip our troops when Cameron himself still can’t come out and say what he’ll do with his own cabinet.” Behind the scenes, “sources close to Corbyn” could usefully soothe pro-European nerves: “As an internationalist party, our inclination is of course to remain within the European family, but it would be irresponsible to declare our hand now, leaving Cameron to barter away British employment rights.” However Corbyn votes himself, it is perfectly plain that he will not have the authority to whip individual Euro-enthusiast MPs to vote against their consciences, so he may as well concede that at once.
(3) We bartered for almonds and olives in the market, where there wasn't another tourist to be seen, and sat on the ramparts, watching the sun fall away beyond the horizon.
(4) It is "our only remaining bartering tool" one union leader said.
(5) The real bartering will be around the question of an acceptable definition of inequality.
(6) The question for the White House now is how the Copenhagen agreement will affect its ambitions to present Congress with a wide ranging energy bill that would enshrine a cap-and-trade system for reducing emissions through bartering.
(7) Women's rights have become a kind of bartering chip to be traded away for political agendas that have little or nothing to do with the interests and wellbeing of women and girls."
(8) People worked long hours for little, bartering farm produce for the few store-bought necessities.
(9) Leveson said her testimony was evidence that the family had been "targets of press intrusion" and felt there "was no remedy apart from bartering away your privacy".
(10) Once he had assembled his cast in the rehearsal rooms, Lepage mixed in some of his own family folklore, the tale of a grand-uncle who became so indebted to Chinese gamblers that he was forced to barter his pregnant daughter.
(11) This shows that restrictions on commercial and barter transactions, to be imposed by the authorities, are required.
(12) It leaves Arsenal with mixed feelings as the summer bartering comes to an end.
(13) If comics have to start bartering for groceries, their dignity's gone for good.
(14) A senior Russian government official – who spoke to Reuters – said separately that Russia has started supplying grain, equipment and construction materials to Iran in exchange for crude oil under a barter deal.
(15) We speculate that the enrichment of polyunsaturated fatty acids on the cell membranes may represent a condition favoring the lipoperoxidation and therefore the development of the retinitis pigmentosa characteristic feature of Laurence-Moon-Barter-Biedl Syndrome.
(16) The Kalunga have a cooperativist society and money is not frequently used as they favor the barter system.
(17) The rebels have described the kidnapped Europeans as prisoners of war and said they might be bartered for imprisoned pro-Russian activists in Kiev.
(18) Russia also said it has struck a barter deal with Iran, exchanging Iran oil for Russian grain and other commodities, although traders said they saw no sign of any increased shipments of either.
(19) Barterers are shown to be the heaviest drug users, using the greatest variety of drugs, using larger amounts of drugs, and using more frequently.
(20) By day, guests loll in the lounge area or sun themselves on the beach, bartering for fresh catch with local fishermen when they return from the sea in the afternoon.