Can you please define Exodus 22:18 as it relates to when it was written and today?

The Law was given to the Jews and pertained to them and those who lived in Israel.

Today, for the Christian, it pertains to the Christian and all who pretend to be Christians. Not that we kill them, as we do not have that authority, we are under the spirit of the Law, and so anyone who calls themselves a Brother in Christ and practices any of these things, is disfellowshipped. Their influence is killed. That is how we are instructed to deal with such matters.

What the world does, it does, and has no bearing on the Christian--they will be dealt with in the next age and brought to a full knowledge of God.

Exodus 22:18 "Thou shalt not suffer a witch to live."

This witch includes both men and women that deal with sorcery, or the demonic spiritual world of Satan. Most of the witches that parade around to sell their lies today, do not fit in this category. The witch at this time was one that would have contact with a devils, fallen angels. Deuteronomy 18:14 describes it as "This enchantment that shows the reality of intercourse with evil spirits (fallen angels) and demons." That is what happened in Genesis six to where the fallen angels [Nephilim], "sons of God" came down to marry the daughters of men, and to have "children" by them. "Children", or Rephiam or Giber were born to them, and by the time of Noah, the entire population was infiltrated with this polluted blood of the fallen angels that was not of flesh man. Remember it was through Noah that the Christ would be born into the world in the flesh, and the great sin was polluting that blood line. It was not any different in Moses' day, than it was in Noah's day. This was the cause of the flood of Noah's day.

It was just another piece of divine legislation for the ancient Jews under the Old Covenant. Now it simply reminds us that God hates sorcery.

Back then, it means what it says.

Today, we're not under a theocracy or OT civil law, so we cannot execute them; but sorcery is still a grave sin.

The language is a bit outdated...

"Do not allow a sorceress to live."

I think in today's context it would have read "educated woman".