Māori is a term used primarily as a cultural/ethnic identifier. That is to say, it is used to label a group of people, the descendents of the aboirginal inhabitants of New Zealand at the time of European arrival. It's meaning is constructed and expressed in the context of other ethnic/cultural signifiers particularly Pākehā (European New Zealanders) and, later, Pasifika, Asian and more.
There is another way, however, of thinking about 'Māori'. Originally the word 'māori' meant 'natural'. This referred to something that lacked impurities, something that naturally and organically appeared in the world. An example is 'waimāori' or pure water.
Historically when children were considered for entry into the whare wānanga (institution of higher learning), the elders would sit and study each child to understand the qualities that were naturally appearing in each child, prior to any teaching. The elders were concerned to understand what energies and qualities naturally, spontaneously and organically manifested and expressed themselves in a child. They would debate with each other about the qualities they saw. Essentially, they were debating the 'māoritanga' of the child, what was naturally appearing in the child. When they had decided what qualities they believed were expressing themselves in a child, it was their view that an atua (deity, god) was drawing the child, the child was naturally the pathway for that atua to express itself. This was it is also meant (among other things) by the terms 'atua māori'. The elders would then dedicate (tohi) that child to that atua and impart to him/her all the knowledge pertaining to that atua.
Now in thinking about this idea, I find it liberating when thinking about my own 'Māoriness'. When one initially begins to learn one's 'Māoritanga' we gather information and knowledge which helps us feel, act and think like a 'Māori'. However, now that I am a little older, I find myself thinking about what naturally and organically springs within me without the aid of any learning or teaching. I find this a deeper way of thinking about my 'māoritanga'. I also find that this a journey toward authenticity, finding my own authentic centre (Māori Marsden uses the term 'authentic being), recovering it, understanding it and letting it flow.