Borisim is “Bodhicitta” in Sanskrit. This is the combination of enlightenment(bodhi, bori) and mind(citta, sim). So it is translated as “mind of enlightenment”
Then what is the mind of enlightenment?
If you got enlightened, it means that you have wisdom of emptiness and lead your life for all beings’ eternal happiness.
So there are two kinds of Borisim, Relative one and Absolute one.
Relative Borisim is the mind you have to cultivate for your enlightenment. It is the determined mind to attain full enlightenment for the benefit of all beings, based on compassion.
Absolute Borisim is the mind of enlightened one with insight of the wisdom of emptiness. In this level, you don’t need to cultivate compassionate mind. Because through the wisdom of emptiness, great compassionate mind just arises spontaneously.
All Buddha’s teachings can be said “Wisdom and Compassion”. If you meditate on emptiness and cultivate compassionate mind, you are the very practitioner of Borisim.