Parapsychology subject (3)
I believe the answer is:
esp
'parapsychology subject' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for esp that I've seen before include "Apparent power to perceive things that others can't, initially" , "Initially, clairvoyance or telepathy" , "Second sight (abbr)" , "Extrasensory perception (abbrev.)" , "Apparent power to perceive things that others can't, in short" .)