Put Your Foot in Your Mouth

Etymology:

• In 19th and 20th century when this expression originated referring to an infectious disease called “foot and mouth disease”, but today this phrase has nothing to do with that disease. We know that only babies put foot in their mouths, not elders. The expression suggests when someone makes blunder by saying something wrong, even without realizing it. He could not have said something wrong if his foot was in his mouth.