Guru means dispeller of darkness, bringer of light. Guru means spiritual teacher, a spiritual master who has attained God - Realization and God - Union, before beginning to teach. A spiritual guru dissolves spiritual ignorance through sharing her / his light and teachings. Satguru means teacher of divine truth.
When the transformational process is all done there is the energy of divine grace that pours forth effortlessly through the being and the mind of the Realized. Grace is a subtle vibration that comes from Truth and pours through the state of pure mind, through Oneness - consciousness. There is a radiance of grace that reaches vastly in every direction all around the Realized. Grace moves inter - dimensionally as well and reaches people one may never have met through the ethereal fields. Grace is a profoundly powerful blessing force that begins to restore everything back into perfect beauty and love. Grace is limitless and unstoppable, perfect and effortless.
When Realized, after full Realization, one must understand that one is now a great field of intense grace and people will unknowingly react to this grace that one radiantly walk around with and as. Some people react with love and adoration (still thinking of it as something outside of themselves) and some people attack, ridicule, confront, antagonize, rebel and so on, angrily protecting their egos that are touched by grace and are beginning to transform.
Guru's grace, the radiance of light and grace happens by itself, is spontaneous and effortless. It is the effortless Presence of the Being of the Divine. It is nothing one does or can do by will. Being a guru is not a task or role to be played out. It is not something that is done with effort and one cannot will it to be or stop it from being. Guru is the mere radiance of divine light and grace. And it affects the surroundings whether one walks down the street, sits in conversation or silence, sleeps, does dishes or stays hidden in the forest or on the mountain top. It happens all the time. It actually radiates far beyond ones immediate surroundings into a radius of many miles and inter - dimensionally as well. It affects all grids, the Earth grid and the Universal grid and transforms everything, the whole Universe. The reach of a fully realized being is immense.
One doesn't have to take the role of teacher, one must not sit in front of audiences or offer satsang and all of that. But one can. One may offer direct support to others who are also awakening, but that alone is not what makes a guru, the radiance is.