immoral vs sinful

immoral

adj
  • Breaching principles of natural law, rectitude, or justice, and so inconsistent with the demands of virtue, purity, or "good morals"; not right, not moral. (Compare unethical, illegal.) 

sinful

adj
  • Constituting a sin; morally or religiously wrong; wicked; evil 

  • Having sinned; guilty of sin. 

  • decadent (luxuriously self-indulgent) 

How often have the words immoral and sinful occurred in a corpus of books? (source: Google Ngram Viewer )