adder

Unable to hear anything. The deafness of an adder is referred to in the Bible. A: "I'm shouting, and he's ignoring me!" B: "Oh, he's deaf as an adder! Write down whatever you're trying to communicate to him." What are you, deaf as an adder? You hear me calling you for dinner, so get in here!

deaf. (*Also:as ~.) When my cousin was a teenager, she played her drum set without ear protection, and she was as deaf as a post by the age of twenty-five. Mark can't hear you even if you shout; he's deaf as a post.

Also, deaf as an adder. Unable to hear or to listen, as in Speak louder, Grandpa's deaf as a post. The first simile has its origin in John Palsgrave's Acolastus (1540): "How deaf an ear I intended to give him ... he were as good to tell his tale to a post." It has largely replaced deaf as an adder, alluding to an ancient belief that adders cannot hear; it is recorded in the Bible (Psalms 58:3-5).