Tohu means nothing, empty, formless, void, vain, meaningless. Put it together with the similar word bohu and there is a rhyme, as in:
‘Now the earth was formless and empty…’ (Genesis 1:2)
The earth was tohu wa bohu. (The same rhyme is in Jeremiah 4:23.) But God gave it shape and purpose:
‘…he did not create it to be empty, but formed it to be inhabited – he says: ‘I am the Lord and there is no other. I have not spoken in secret from somewhere in a land of darkness; I have not said to Jacob’s descendants, ‘Seek me in vain.’ I, the Lord, speak the truth; I declare what is right.’’ (Isaiah 45:18b,19)
In Isaiah 24:7-9 much of society’s apparent sophistication is listed and then seen as empty.
‘The ruined city lies desolate.’ (Isaiah 24:10a)
Without God’s ongoing hold on creation the world is empty. Without him our lives are purposeless.