Imagine someone that is deceitful, selfish, greedy, self-indulgent, and yet enjoys great pleasure and appears to be quite happy. Is someone like this “flourishing” or not?

The idea that someone is "flourishing" is difficult to define as the notion is quite subjective. Personally, I wouldn't say that someone who is selfish, greedy and all of the other things you mentioned is flourishing; quite the opposite. But it really comes down to personal opinion.

Some people thrive on only looking out for themselves and being selfish and greedy. They seemingly take no pleasure in things which might naturally make us happy, like friends and family, and sharing their lives with others.

That said, how can we really know what makes people happy? Sometimes people's insecurities or bad past experiences lead them to mistrust other people. They don't see 'flourishing' in life as letting other people in, but at the same time that doesn't always mean that they are happy.

And if you're a believer in karma and the idea of "what goes around comes around" then you can be safe in the knowledge that these people will not be flourishing for long!