what is an equivalent for 'fitna'?

Solution 1:

As you mentioned, it is a general concept and it is not only related to politics or religion (even though it usually shows itself in these domains.)

I think an equivalent (or near-equivalent) word is instigation or even mischief-making. Also, it can show itself as a provocation. But these words may not cover all the meanings of the word.

When you instigate something, you start it, but the word carries conflict with it. If you are suspended for wearing a political t-shirt, the incident might instigate days of protest by students and faculty.

Instigate comes from the Latin word instigare "to incite." People who are instigators often begin trouble but then back off and let others break the rules.

http://www.vocabulary.com/dictionary/instigate

Though, as a terminology, it is used as fitna or fitnah in English and it gains different meanings in different domains. There are even differences between the meanings of the term in Classical Arabic and Modern Arabic. ^Wikipedia