A difficulty with the word ‘nibbāna’ is that its meaning is beyond the power of words to describe. It is, essentially, undefinable.
Another difficulty is that many Buddhists see Nibbāna as something unobtainable – as so high and so remote that we’re not worthy enough to try for it. Or we see Nibbāna as a goal, as an unknown, undefined something that we should somehow try to attain.
Most of us are conditioned in this way. We want to achieve or attain something that we don’t have now. So Nibbāna is looked at as something that, if you work hard, keep the sīla, meditate diligently, become a monastic, devote your life to practice, then your reward might be that eventually you attain Nibbāna – even though we’re not sure what it is.