Wiktionary
deaf as a post
a. (context simile English) stone deaf (gloss: unable to hear at all)
WordNet
deaf as a post
adj. totally deaf; unable to hear anything [syn: profoundly deaf, stone-deaf, unhearing]
Usage examples of "deaf as a post".
I won't talk in front of Block if you don't want me to, but it's quite plain he's as deaf as a post!
However, he got a bit more serious after that, and he said that actually he had gone home before stepping down the street to the Red Lion, though he didn't think he could prove it, because so far as he knew Mrs Blindburn -- that's his housekeeper -- couldn't have seen him, being in the kitchen, and certainly wouldn't have heard him, because she's as deaf as a post.