Dictionary.com
antinomian
noun
- a person who maintains that Christians are freed from the moral law by virtue of grace as set forth in the gospel.
Etymonline.com (antinomian)
“one who maintains that, by the dispensation of grace, the moral law is not binding on Christians,” 1640s, from Medieval Latin Antinomi, name given to a sect of this sort that arose in Germany in 1535, from Greek anti “opposite, against” (see anti-) + nomos “rule, law,” from PIE root *nem- “assign, allot; take.” As an adjective from 1640s.
Discussion/Explanation
The definitions above do a great job of getting to the point of the term – despite them being more focused on individuals who hold this view (the ism).
Antinomianism is one of the pitfall beliefs out there as it effectively rejects entire sections of the Old Testament and what it has to say about how we order our lives. Some fall into this line of thinking out of ignorance but others do it deliberately
See more like this post in “ologies & key terms“.