There is an old saying, "define or be defined."
Theonomy is most concisely defined as the following.
"The biblical teaching that Mosaic Law contains perpetual moral standards for living, including some judicial/civil laws, which remain obligatory for today. As well as civil magistrates refraining from coercion in areas where God has not prescribed intervention"
It doss not mean going on a death penalty rampage of all people breaking those Laws. Nor that you even necessarily agree with enforcing The First Table of the Law of the Ten Commandments. Theonomy is a spectrum and not every theonomist agrees with every over theonomist on all the details of how God's Law is manifest or enforced in the modern day only that it is to be enforced.
I would recommend Joel McDurmon's wonderful book, "The Bounds of Love." It cuts through the misunderstanding about theonomic ethics and Theonomy. The simple definition presented in this article is from his book.
