On the radio this morning I heard that this word, flexitarian, won an award for being one of the best new coinages. As you can see from this link, it is someone who eats mostly vegetarian, but will eat meat on occasion. For flexitarians the diet is chosen for health reasons, not out of concern for animal rights.
In fact it was the word of the week on bestweekever.
Similarly, back in the 60's there was the drug known as "HTT" as in "I'm not a major user but I'll occasionally do some HTT."
"HTT" stood for "Here, take this" and the above quote indicated that the speaker would pretty much take any drug as long as he/she didn't have to pay for it, illicitly flexitarian as it were.
It was a fun enough term but I don't think it ever caught on.
I suspect that "flexitarian" won't catch on either. It seems vague to me. After all, we all think about our diet, and too much meat, from time to to time. Is anyone who isn't a "vegetarian" a "flexitarian" then?