Green’s Dictionary of Slang

rip-off n.

also rip, ripoff

1. (orig. US) a fraud, a cheat, a disappointment; also attrib.

2. an act of theft or robbery; also attrib.

3. something stolen or plagiarized.

4. (US prison) a physical attack.

5. a thief.

In compounds

rip joint (n.) [joint n. (3b)]

[1970s+] (US campus) any store that charges exorbitant prices to students.