Question: Generally speaking , what kind of vow cannot be annulled?

Answer: In Judaism, if a Jew makes a vow not understanding something about the vow he was making, AND, if he did understand he would never have made that vow, then, in general, it would be possible for such a vow to be annulled. That is the simple question to a not-so-simple subject.

Regards, Eliahu Levenson