big empty talk: boasting or babble with nothing behind it, and in the plural the boasters and fortune tellers who trade in it
This is a small, scornful word for talk that sounds impressive and turns out to be hollow. It appears in the prophets' verdict on Moab, whose pride was famous and whose swagger was loud, and the line simply says that its big talk is worth nothing. Job's friend Zophar uses the same word to wave off Job's speeches as noise that has bullied everyone else into silence.
The word is usually traced to a verb meaning to make something up out of nothing (בָּדָא), and that fits the way it is used. It is not the ordinary word for a false statement (שֶׁקֶר), which accuses a speaker of knowing better. The charge here is emptiness: sound without substance, claims with no weight behind them.
From the talk the word slides to the talkers. In the plural it names the people whose whole business is such words, and twice those people are the professionals: the readers of signs whose forecasts God turns into nonsense, and the specialists of Babylon whom the sword will expose as fools. Set beside the plain Hebrew verb for practicing divination (קָסַם), this word is mockery rather than a job title. It calls them windbags.
Two of the seven places are argued over, because Hebrew has other, unrelated words spelled exactly the same way. In the poem about Leviathan in Job, most translations take the word as the creature's limbs; in Hosea's warning about the sword, many take it as the bars of a city's gates. Both are kept with this word below, following the reading that hears empty talk in them, but the ground under them is soft.