Synonyms for Iniquity (same or very similar meaning)
WordNet sense 1 (absence of moral or spiritual values):
dark, darkness, wickednessWordNet sense 2 (morally objectionable behavior):
evil, immoralityWordNet sense 3 (an unjust act):
injustice, shabbiness, unfairnessFrom the ODE community, based on WordNetadd/edit