1. Reassuring a friend that, because ze’s a good person deep down inside, that what ze did wasn’t really that bad after all, and was in fact what anyone else would have done in the same situation.
2. Among Christians - Helping a friend find an obscure verse in the Bible or theological contrivance to support a decision they’ve already made, to assuage a guilty conscience.
Example: "You need to be the parent, not the friend. If you had let her continue to live with you, she’d think it’s okay to be gay. It’s really not so bad being homeless as a teen, anyway - it’s kind of an adventure if you think about it!"
Added to Urban Dictionary - It was approved and should be appearing soon: http://www.urbandictionary.com/define.php?term=immoral+support