Deception, Denial and Delusion

We started an interesting conversation with Cindy Anthony on deception versus denial yesterday. How can we tell when a person is being deceptive versus when they are in denial? As I thought about it, I also wondered how to differentiate delusions in all of this (outside of psychosis)?

Denial, defined by the FreeDictionary.com, is medically defined as “a primitive–ego defense–mechanism by which a person unconsciously negates the existence of a …stress-producing reality in his environment.” I’ve seen other places add “in the presence of overwhelming evidence to the contrary”.

Delusion, defined by the Free Dictionary.com, is defined as “a belief held in the face of evidence to the contrary, that is resistant to all reason.”

I feel I have a good understanding of these, but I am not able to verbalize it so I thought it would be fun to see if we as a group can narrow these down and create a list of how to determine if someone is each of these things. What differentiates each of these? What are unique attributes to each of them?