That dog don't hunt......I love it, I used to say that, was one of my favorite sayings. Guess it comes from us country folk. I got a big kick out of seeing it here.
Let's see....if we were all sitting around brainstorming ideas and someone said "That won't fly"...it is kind of the same.
Used to men hunted. For meat and sport. That dog won't hunt means it won't work, it's useless, ...I guess better translated...."I don't believe that" would be the best way to explain "That dog won't hunt"....and "I am not buying it."