Noun
An advocate of immorality
An adherent or practitioner of immoralism
Source: en.wiktionary.orgNietzsche himself was a great moralist; his writings abound with value judgments about individuals, character types, modes of thinking, and national traits. It is as if he develops immoralist psychology in order to tame his own nature, to keep his own greatest vice in check. John Carroll
It naturally follows that the creature you love next best is the person - the God-lover or God-hater (almost never, apparently, anything in between), the saint or profligate, moralist or complete immoralist - who can write a poem that is a poem. J. D. Salinger