Buddhism teaches that there are four levels of enlightenment. The first level is called Stream Enterer. A Stream-Enterer is a person who has penetrated with profound understanding the basic essence of what we are, or you could say what we are not, something that is often referred to as Anatta. It is translated into English with various different words, non-self, no-self, sometimes the word voidness is used to complement it. The Stream Enterer is said to have a deep experiential understanding of Anatta.
The second level is called a Once-Returner, which means that they are more purified than the Stream-Enterer. They have drastically reduced anger and desire to a great extent. The third level is called a Non-Returner. This person has totally ended sense desire and aversions. They are purified on that level. But as I said a minute ago, they still have conceit, they still have thoughts of I am and a few other little mental things they work on. The fourth level is total purification, called Arahant. A perfectly pure beautiful human being, no more anger, no more fear, no more conceit at all. So Buddhism teaches there are these four levels.
There is not really such a thing as "half enlightened", but there are these four levels, and we would say for the first three that they are partially enlightened, rather than the word "half", and then the fourth is of course full enlightenment. The first two levels also have a characteristic that a person can actually be a lay person, can still have family, can still have sex, raise kids and so on. On the first two levels they will still have a degree of sense desire. The third level, the non-returner has destroyed all sense desires, so they would no longer have sexual relationships and that sort of thing, but they can still be a lay person. The fourth level, when a person is fully enlightened, they say that they would totally avoid being a lay person, that they would ordain at that time, if they are not already.