lib·er·tar·i·an (lbr-târ-n) n.
1. One who advocates maximizing individual rights and minimizing the role of the state.
2. One who believes in free will.
libertarian1 : an advocate of the doctrine of free will
2 a : a person who upholds the principles of absolute and unrestricted liberty especially of thought and action b capitalized : a member of a political party advocating libertarian principles
Merriam-Webster, http://www.m-w.com
Jefferson and the other members of the committee that wrote the Declaration of Independence weren't Libertarians, or even libertarians, your nameless "dictionary" notwithstanding.