1) to act emptily, become vain, be vain

1a) (Qal)

1a1) to become vain

1a2) to be utterly vain (with cognate acc)

1b) (Hiphil)

1b1) to cause to become vain

1b2) to fill with vain hopes

Root √הבל: הֶ֫בֶל n.m vapour breath 73.

הָבַל vb. denom act emptily become vain Qal became vain they went after vanity and Hiph cause to become vain .(of false prophets) i.e. fill you with vain hopes.