Actually, this is a very interesting question I think. To be honest, I had never researched the term antinomianism. I should have put it together. Greek for law is nomos, therefore one who is against the law. I understand now that Martin Luther coined the phrase when he was accused of rejecting the law of God completely. I can also see from the perspective of a people in Luther's day whose entire concept of salvation was bound up in the keeping of rites, rituals, and laws that the concept of justification by grace was a pretty big shock. I can see them reacting violently and proclaiming, "That man Luther is teaching that the law is totally abrogated."
But then I realize this was the reaction of the Pharisees to Christ's preaching and to the subsequent preaching of the early church. Luther wrote a treatise against antinomianism. Jesus and Paul made some similar statements.
Mat 5:17-19 Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfil. (18) For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled. (19) Whosoever therefore shall break one of these least commandments, and shall teach men so, he shall be called the least in the kingdom of heaven: but whosoever shall do and teach them, the same shall be called great in the kingdom of heaven.
Rom 7:1-13 Know ye not, brethren, (for I speak to them that know the law,) how that the law hath dominion over a man as long as he liveth? (2) For the woman which hath an husband is bound by the law to her husband so long as he liveth; but if the husband be dead, she is loosed from the law of her husband. (3) So then if, while her husband liveth, she be married to another man, she shall be called an adulteress: but if her husband be dead, she is free from that law; so that she is no adulteress, though she be married to another man. (4) Wherefore, my brethren, ye also are become dead to the law by the body of Christ; that ye should be married to another, even to him who is raised from the dead, that we should bring forth fruit unto God. (5) For when we were in the flesh, the motions of sins, which were by the law, did work in our members to bring forth fruit unto death. (6) But now we are delivered from the law, that being dead wherein we were held; that we should serve in newness of spirit, and not in the oldness of the letter. (7) What shall we say then? Is the law sin? God forbid. Nay, I had not known sin, but by the law: for I had not known lust, except the law had said, Thou shalt not covet. (8) But sin, taking occasion by the commandment, wrought in me all manner of concupiscence. For without the law sin was dead. (9) For I was alive without the law once: but when the commandment came, sin revived, and I died. (10) And the commandment, which was ordained to life, I found to be unto death. (11) For sin, taking occasion by the commandment, deceived me, and by it slew me. (12) Wherefore the law is holy, and the commandment holy, and just, and good. (13) Was then that which is good made death unto me? God forbid. But sin, that it might appear sin, working death in me by that which is good; that sin by the commandment might become exceeding sinful.
The law, when used lawfully, still performs its intended function today. It is not done away with. But it was never intended to be used to obtain or to maintain righteousness. But to a people who had always believed that righteousness could be attained by keeping the law, be it Pharisees or the church of Luther's day, the idea that all of their hard work was for nothing was a bitter pill for their flesh and pride to swallow.