Wiktionary
vb. (present participle of bark up the wrong tree English)
Wikipedia
Barking up the wrong tree is an idiomatic expression in English, which is used to suggest a mistaken emphasis in a specific context. The phrase is an allusion to the mistake made by dogs when they believe they have chased a prey up a tree, but the game may have escaped by leaping from one tree to another. The phrase means to mistake one's object, or to pursue the wrong course to obtain it.
In other words, "if you are barking up the wrong tree, it means that you have completely misunderstood something or are totally wrong."
Usage examples of "barking up the wrong tree".
At first, it seemed as if the Baudelaires were barking up the wrong tree, because the water seemed to have no more effect against the wall of the Deluxe Cell than a silk scarf would have against a charging rhinoceros, but it soon became clear that water —.
The Baudelaire orphans had been barking up the wrong tree all evening, because the only thing the children found that morning was another scrap of paper, rolled into a scroll, among all the black feathers that the crows had left behind.
He was barking up the wrong tree, though, if he thought a job applicant would be one of his runaways.
Naturally I should have been all in favour of that, but I was barking up the wrong tree.
But as I don't happen to be interested in a blonde, and even if I met one, am too busy just now to run after her, Madame Zero, or whatever she calls herself, was barking up the wrong tree.
I knew my wife was barking up the wrong tree, so I decided to let her go, feeling she might calm down after she found out her mistake.