Considering capitalism was originally a slur word used to describe mercantilism which is not an example of a free market, I tend to avoid it also.

In truth very few of us have ever been exposed to an actual free market so people's view on this is skewed by that perspective. I usually try to point out the collusion between corporations and the state and how that raises the barrier to entry into the market place and makes it impossible for most individuals to compete.

I am generally pretty successful unless I'm talking to a die hard commie.