A knock off

Idiom: A knock off

Example 1:

Brandon: Wow, Melissa! Nice bag. It looks really expensive!

Melissa: Thanks, Brandon! Shh. don't tell anyone, it's a knock off. It only cost me $15. The original is over $1,500! It's a pretty good knock off. It looks pretty authentic.

Example 2:
Scott: Jessie, look at these toys. These are terrible knock offs!
Jessie: Ha ha ha! Mickey Mouse isn't supposed to look like that!

Meaning: "A knock off" (noun) is a copy of an original item. This expression is often used when the original item is of designer quality and very expensive. This expression has slightly negative connotations that imply that the copy is of very cheap quality and design.

You can learn more idioms like this in LSI's Intermediate and Advanced Conversation Programs. 

Please see: idiomstudy.blogspot.com for more information.