In Buddhist practice, it is said that while samatha meditation can calm the mind, only vipassana meditation can reveal how the mind was disturbed to start with, which is what leads to insight knowledge (jnana; Pali nana) and understanding (prajna Pali panna), and thus can lead to nirvana (Pali nibbana). When one is in jhana, all defilements are suppressed temporarily. Only understanding (prajna or vipassana) eradicates the defilements completely. Jhanas are also states that Arahants abide in order to rest.
Try to answer this question if possible (otherwise reply "unanswerable"): What is the term for understanding?
prajna