(n.) knockoff - a copy of an original brand, often priced dramatically lower than an authentic. Commonly, the designs will have been altered a bit, or they will appear the exact same, but some small detail may prove they are not authentic.
"Woah, a Dior wallet for $40.00? That can't be possible."
"It isn't. See? The interior isn't leather, it's plastic. And the stitching is loose and falling apart. It's definitely a knockoff."