An antinomian is one who is against the law of God, a lawless person (I John 3:4). An antinomian is one who seeks to destroy, or nullify God's law. Though antinomianism is a scurrilous charge laid against those who believe and preach the gospel of God's free grace in Christ, none of God's saints are antinomians. Anyone who is against God's law is against God's holiness, which means that he is against God. To say that a person is an antinomian is to say that he is lost.
It has always been the practice of legalists to charge those who preach salvation by grace alone, through faith alone, in Christ alone, without works, with antinomianism. Those who despise the gospel of God's free and sovereign grace, because they cannot refute the doctrine of the gospel upon biblical grounds, seek to destroy the name and reputation of the man, or the congregation, that preaches the gospel. They do so by attempting to spread the slime of antinomianism upon his character. And they defend their actions under the pretence that they are upholding the law of God which says, "Thou shalt not bear false witness against thy neighbor" (Ex. 20:16)! The Pharisees charged our Lord with being a glutton and a winebibber, who had come to destroy the law, while in reality he honored it, fulfilled it and established it and they despised it, nullified it and lowered its standards to their wicked lives. It was not Christ, but the Pharisees who were antinomian. The judaizers at Galatia charged Paul with antinomianism, accusing him of promoting lawlessness and licentiousness. In the name of honoring the law, they spread scandalous charges against the man whom God had sent to proclaim the only gospel by which his law is honored. It was not Paul, but the judaizers themselves who were antinomian.
It is not possible for us to stop the mouths of wicked men who are bent upon slander. And we must not attempt to do so. God will settle the issue in his own time. But to answer the question "What is an antinomian?", it must be eluded that it is the legalist, the one who teaches that salvation can be either gained or improved by personal obedience to the law, who is the antinomian. In the name of defending the law, he promotes that which is contrary to the law, strife and slander, and lowers the law to the standard of his own pretended obedience to the law. Is that not antiomianism?