What does “world” mean in the Bible?

"World" has several meanings in the Bible. But here is one that is frequent.

The world = the thinking, beliefs (especially values) and desires that unsaved people typically have. And the resulting behaviors. These involve loving the pleasures of this present world, and giving little or no weight to God and the world to come. It usually includes idolizing one’s self, rather than worshipping God.

Romans 12:2 KJV

And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God.

1 Corinthians 1:20 KJV

Where is the wise? where is the scribe? where is the disputer of this world? hath not God made foolish the wisdom of this world?

2 Timothy 4:10A KJV

For Demas hath forsaken me, having loved this present world,

Titus 2:12 KJV

Teaching us that, denying ungodliness and worldly lusts, we should live soberly, righteously, and godly, in this present world;

1 John 2:15-16 KJV

[15] Love not the world, neither the things that are in the world. If any man love the world, the love of the Father is not in him.

[16] For all that is in the world, the lust of the flesh, and the lust of the eyes, and the pride of life, is not of the Father, but is of the world.