A situation in which one thing is pretending to be another. From Lemony Snicket's A Series of Unfortunate Events, Book 6, The Ersatz Elevator, page 129
"Not only are there no ropes," Violet said. "There's no endlessly looped belt, push-button console, or electromagnetic braking system. I don't even see an enclosed platform."
"I knew it," Klaus said, in hushed excitement. " I knew the elevator was ersatz.
"Ersatz" is a german word and means substitute.
"Hallo Klaus, hast Du das Ersatzrad?"
"Hello Klaus, do you got the spare tire?"
"Der Trainer schickt seine Ersatzspieler rein."
"The coach is sending in his substitute players."
Being an inferior substitute or alternative.
The show "Mad TV" is an ersatz "Saturday Night Live".
Fake, phony; not real.
Look at her, lording it up in that ersatz Gucci outfit...she makes me so sick.