THESAURUS
apostasy, atheism, backsliding, desertion, fall from grace, godlessness, impiety, impiousness, irreverence, lapse, lapse from grace, recidivism, recreancy, sinfulness, un-Christliness, unangelicalness, unchristianliness, undutifulness, ungodliness, unholiness, unrighteousness, unsaintliness, wickedness
ROGET THESAURUS
Irreligion
N
irreligion, indevotion, godlessness, ungodliness, laxity, quietism, skepticism, doubt, unbelief, disbelief, incredulity, incredulousness, want of faith, want of belief, pyrrhonism, bout, agnosticism, atheism, deism, hylotheism, materialism, positivism, nihilism, infidelity, freethinking, antichristianity, rationalism, neology, atheist, skeptic, unbeliever, deist, infidel, pyrrhonist, giaour, heathen, alien, gentile, Nazarene, espri fort, freethinker, latitudinarian, rationalist, materialist, positivist, nihilist, agnostic, somatist, theophobist, irreligious, indevout, undevout, devoutless, godless, graceless, ungodly, unholy, unsanctified, unhallowed, atheistic, without God, skeptical, freethinking, unbelieving, unconverted, incredulous, faithless, lacking faith, deistical, unchristian, antichristian, worldly, mundane, earthly, carnal, worldly minded, irreligiously.