Vanity, Vain – pointless or without purpose, inutility, empty, worthless, moral depravity, wickedness, counterproductive.
Ecclesiastes being the great book of vanity, I will use references from other books.
II Kings 17:15 And they rejected his statutes, and his covenant that he made with their fathers, and his testimonies which he testified against them; and they followed vanity, and became vain, and went after the heathen that were round about them, concerning whom the LORD had charged them, that they should not do like them.
Isaiah 41:29 Behold, they are all vanity; their works are nothing: their molten images are wind and confusion.
Jeremiah 51:18 They are vanity, the work of errors: in the time of their visitation they shall perish.
I Timothy 1:6 From which some having swerved have turned aside unto vain jangling;
I Timothy 6:20 O Timothy, keep that which is committed to thy trust, avoiding profane and vain babblings, and oppositions of science falsely so called:
Titus 3:9 But avoid foolish questions, and genealogies, and contentions, and strivings about the law; for they are unprofitable and vain.