The psychological dissection of a human's unconscious mind through the utilization of advanced oneiric technology to determine what nightmarish phenomena is affecting their mentality.
"He suddenly fell into a coma due to a hauntingnightmare he had, so we had to wait for the Oneiropsy report to tell us why he was having genocidal behavior."
A person who is obsessed with nighttime dreams. So much so, that they think about dreaming when they are awake. Someone who has a deep and intimate connection with dreaming. This person is likely to be a lucid dreamer.
Guy 1: Mark NEVER stops talking about dreams!
Guy 2: That is because he is an oneirophile