muff (one's) lines(redirected from muffed lines)
muff (one's) lines
To forget or bungle the words that one is supposed to say, as in a speech or play. My mind went completely blank as soon as I stepped on stage, and I totally muffed my lines. I had learned the speech off by heart, but I was so emotional that I started muffing my lines about halfway through.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.