To act emptily, to become vain, to lead astray, to be futile
Brown-Driver-Briggs Hebrew Lexicon
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