antinomian
noun
an·ti·no·mi·an ˌan-ti-ˈnō-mē-ən 
1
: one who holds that under the gospel dispensation of grace (see grace entry 1 sense 1a) the moral law is of no use or obligation because faith alone is necessary to salvation
2
: one who rejects a socially established morality
antinomian adjective
antinomianism
ˌan-ti-ˈnō-mē-ə-ˌni-zəm
noun 
Word History
Etymology
Medieval Latin antinomus, from Latin anti- + Greek nomos law
First Known Use
1548, in the meaning defined at sense 1