rip off

1.  Steal, as in They fired him when they caught him ripping off some of the merchandise.
2.  Cheat, defraud, as in These advertising claims have ripped off a great many consumers.
3.  Copy, plagiarize, as in He was sued for ripping off someone else's thesis. All three usages are slang from the second half of the 1900s.

Definition: rob; trick
Antonyms: give, offer

To the rebellious, politically radical youth of the late 1960s, steal was too bourgeois a word. It implied criticism of the act of "liberating" wrongfully acquired property that had been stolen from "the people" by "capitalist pigs." So they ripped off that verb from urban African-American slang, as in a 1967 article in Trans-Action: "The hustler burns people for money, but he also 'rips off' goods for money; he thieves, and petty thieving is always a family hustle."

Rip off appears in a 1970 New Yorker article in words shouted by a young woman: "We're sitting here, and Chemical Bank is gloating about how they're going to rip us off! Well, we're going to go into the streets and rip you off!"

By 1970, rip-off was a noun too, in the service of the radicals' "class struggle." A publication of that year defined rip-off as "capitalist exploitation."

As the New Yorker article indicates, rip off also was useful in expressing outrage on the part of innocent victims. So in a 1971 issue of the magazine Frendz, we find, "The young people are well aware that they are being ripped off by these parasites, and, quite naturally, think that the visiting musicians are on the side of the promoters." Not long thereafter rip off is also found in the sense of "plagiarize."

The radicals of the '60s and '70s have yielded to the conservative Yuppies (1984) and apolitical Generation X (1991), but ripped off remains a forceful term to use to protest against maltreatment.

The verb has one meaning:

Meaning #1: deprive somebody of something by deceit
  Synonyms: cheat, beat, chisel