Though I technically consider myself an Opportunisar, I just found the following article that offers the alternative categorization of “Flexitarian”:

http://www.mayoclinic.com/health/vegetarian-diet/HQ01596/

All dietary implications aside, Flexitarianism has a great ring to it. You could apply it to so many more things than diet:

“Hi there, I’m from your local Flexitarian Church and I wanted to invite you to attend…. or not. You know, whatever. We meet on Sundays sometimes, or Thursdays. It varies. I can leave some literature for you to look at, but I won’t this time. Maybe next time though.”