It is a slang and means : a. to steal or pilfer. b. to rob or steal from. c. to swindle, cheat, or exploit; take advantage of: phony charity appeals that rip off a gullible public. If someone rips you off, they cheat you by selling you cheap stuff not worth the money they are charging or by getting more money out of you. They can also steal your ideas, work and claim it as their own.

If you rip someone off, you steal something from that person (usually something they say, or an idea they came up with) and claim it as your own. If something is a rip off, then it is not worth the price (for example, a pen that you bought for $10 that breaks the moment you use it.)

yeah to cheat

Yes it means to cheat.