I am also replying to your comment to Michael about having to "summarize it". By "it", did you mean the article or the definition?
If you must only summarize the article, everything you need is there in the article. Read it, understand it, then say it in your own words.
I have never heard this phrase before, but it is an interesting one. If you are required to do more than summarize, you may want to ask yourself, from your own experiences, do you agree with the article? If you do agree, examine the reasons. If you don't agree, examine the reasons. If you think it is only true in some cases/situations, examine those too. Once you sort these things out, it will be easier to write something.
The definition of passive tolerance seems to be (from this article) that the more you are exposed to something you may be intolerant to, the more tolerant you become of it.