Definition - What does Satguru mean?
Satguru, or sadguru, is the title given to one whose life purpose is enlightenment through Self-realization of the ultimate Truth. The literal Sanskrit translation is “the true guru.”
A satguru is an extreme rarity. Characteristics of a satguru are much different than those of a guru. A guru is acquainted with his/her own personal truth, whereas the satguru has realized the Supreme Truth.
Yogapedia explains Satguru
One that is beyond duality remains unaffected by abuse or pleasure and lacks all other contingent attributes that may distract from enlightenment. The guru who is free from duality is a satguru.
The satguru is aware of the absolute Truth, which is comprised of all fathomable truths. He is the preacher of all fundamental secrets and teacher of true Self-realization. A satguru is one who liberates us from suffering (through his/her example) and encourages direct contact with the Self.