He has an eye to the future (4)
I believe the answer is:
seer
'he has an eye to the future' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he has an eye' is the wordplay.
'he' becomes 'ser' (I can't explain this - if you can you should believe this answer much more).
'has' indicates putting letters inside.
'an' becomes 'per' (synonymous as in 'once an hour', 'once per hour').
'eye' indicates the central letters (eye can mean the centre of something).
The middle of 'per' is 'e'.
'ser' placed around 'e' is 'SEER'.
Can you help me to learn more?
(Other definitions for seer that I've seen before include "One has unusual foresight" , "Prophet, one who has visions" , "Prophet or clairvoyant" , "One who knows the future" , "One fortelling future" .)