From bada'; a brag or lie; also a liar -- liar, lie.
see HEBREW bada'
H907. bad
III. [בַּד] noun masculine only Plural בַּדִּים.
a. empty, idle talk (Phoenician CIS3, 6 listen not to בדנם = Hebrew בַּדֵּיהֶם; compare vain talk), especially with collateral idea of imaginary pretensions or claims: Job 11:3 מְתִיםיַחֲרִישׁוּ בַּדֶּיךָ thy idle talk brings men to silence ("" וַתִּלְעַג), Isaiah 16:6 (of Moab) בַּדָּיו כֵן לֹא his boastings are not right (unfounded), hence Jeremiah 48:30.
b. concrete empty talkers, praters (compare Late Hebrew בַּדָּאָה, Syriac , liar), of false prophets, Isaiah 44:25; Jeremiah 50:36.