When used as an idiom, this phrase means to cheat someone or charge too much money for something. It can also mean to copy someone else’s idea or work unfairly.
Here are some examples:
That shop ripped me off — they charged $50 for a t-shirt! (=the shop charged too much)
That movie totally ripped off Star Wars. (=the movie copied Star Wars)
The phrase ‘rip off’ comes from American slang in the 1940s-1950s. It combines verb ‘rip’ (to tear or take away) and ‘off’ (away or completely).

So originally, ‘rip off’ meant ‘to steal something away from someone.’ Over time, it came to mean ‘to cheat’ or ‘to overcharge.’
‘Rip off’ can be used as a phrasal verb or noun. When used as a phrasal verb, it’s separable which means you can also put the object between ‘rip’ and ‘off’ like below:
✅The guy at the street market ripped me off.
✅That shop always rips off tourists.
When using ‘rip off’ as a noun, it’s spelled with a hyphen. And, when used to talk about a ‘copy’, it’s often followed by ‘of’. Here are some examples:
✅ That bag is a rip-off of a Gucci bag.
✅ The coffees cost us $15.00 each! What a complete rip-off.
Have you ever been ‘ripped off’ and payed too much money for something?
Related links:
Useful phrases for talking about money
What does ‘twist your arm’ mean?