Consult registered clairvoyant (4)
I believe the answer is:
seer
'clairvoyant' is the definition.
(I've seen this before)
'consult registered' is the wordplay.
'consult' becomes 'see' (I've seen this in another clue).
'registered' becomes 'R' (abbreviation, as in registered trademark).
'see'+'r'='SEER'
(Other definitions for seer that I've seen before include "Person who can read the future" , "Oracle or clairvoyant" , "Prophet or visionary" , "One divines the future" , "Prophet, one who has visions" .)