Defecation of character is what happens when someone shits on your name in a public forum.
You: "Oh, man! Brittany just called me a ho on Facebook because I said I liked her crush."
Your friend: "Wow, that's defecation of character."
When someone is talking shit about you.
I thought my ex and I parted on good terms and were still friends; but she was caught in the act by other friends of ours who knew almost everything about us and confronted her for lying about me to make me look bad while committing defecation of character.
Talking shit about your good character; shitting on your good name; spreading lies about you that are not true.
I am going to sue you for defecation of character if you don't stop talking about me and spreading lies.