A neobank is a new kind of bank that is entirely digital, has no physical offices, no bricks and mortar, and generally operates from an app on your phone. It also uses totally new software, quite different from that used by traditional banks and not constrained by legacy issues.
This may sound similar to the online offerings and apps provided by traditional banks but these are developments to old systems. The neobank starts everything afresh. It does however have to fulfil all the requirements of the banking system so that customers have the same safeguards that they would have with traditional banks.