Sixth sense (3,8)
'sixth sense' is the definition.
(extra-sensory perception)
This is all the clue.
(Other definitions for esp that I've seen before include "Second sight (abbr)" , "Apparent power to perceive things that others can't, in short" , "Apparent power to perceive things that others can't, initially" , "Extrasensory perception (abbrev.)" , "Initially, clairvoyance or telepathy" .)
(Another definition for gut instinct that I've seen is " First intuition".)