1. "Scapegoat." Some people say "ESCAPE goat." But a scapegoat is someone who takes the blame. And saying "ESCAPE goat" sounds like you're talking about a loose farm animal.
2. "Biding your time." Some people say "BITING your time," which is wrong. The word "bide" means "to wait for." Saying someone's "biting their time" doesn't make sense.
3. "Play it by ear." It's a music term. If you play it by ear, you're doing it without reading sheet music. Apparently some people think it's "play it by YEAR."
4. "Pass muster," which means you're meeting a certain standard. Some people think it's "pass MUSTARD," which is something you might do at the table . . . or something your digestive system might do after you eat a hot dog.
5. "Moot point" . . . spelled M-O-O-T. It usually means something's irrelevant or hypothetical. Some people say "MUTE point," which is wrong.