Clairvoyant to understand right (4)
I believe the answer is:
seer
'clairvoyant' is the definition.
(I've seen this in another clue)
'understand right' is the wordplay.
'understand' becomes 'see' (synonyms).
'right' becomes 'r' (common abbreviation).
'see'+'r'='SEER'
'to' is the link.
(Other definitions for seer that I've seen before include "Sage with 20ac" , "Oracle or prophet" , "Person of vision" , "Prophet, one who has visions" , "One who knows the future" .)