Originally these words had specific meanings - zionism meant the belief that Jews should have their own "jewish state" and islamism meant a belief that Islam should be implimented politically.

Despite their benign meanings they have very negative connotations in the modern world.

I have also see them thrown around with a great deal of liberality - islamism is often used as a blanket term for terrorism, fundamentalism, or those who call for a return of the caliphate - even though the original meaning did not necessarily refer to these things.

Zionism too is often a blanket term for Israelis, jews, jewish conspiracies, or any kind of oppressive action against muslims by nonmuslims - again this stretches the original meaning of the word.

In their modern context are Islamist and Zionist useful anymore? Are they simply dangerous slurs?