Completely wrong. If you think I'm doing your chores for you, you're dead wrong, buddy! Well, based on these results, my hypothesis is dead wrong.
completely wrong. I'm sorry. I was dead wrong. I didn't have the facts straight.
dead on one's feet
Extremely tired. This graphic hyperbole, with its use of “dead” in the meaning of “utterly fatigued,” is probably related to dead tired, where “dead” means “very” or “absolutely.” This locution has been traced to Irish speech and appears in such clichés as dead wrong for “completely mistaken,” dead right for “absolutely correct,” dead certain for “totally sure,” and others. “Dead on one’s feet” became common in the mid-twentieth century. John Braine used it in Life at the Top (1962): “Honestly, I’m dead on my feet.”