Saint, over a long period of time, is most judicious (6)
I believe the answer is:
sagest
'is most judicious' is the definition.
(I've seen this in another clue)
'saint over a long period' is the wordplay.
'saint' becomes 'st' (abbreviation).
'over' indicates putting letters inside.
'a long period' becomes 'ages' (I've seen this in another clue).
'st' going around 'ages' is 'SAGEST'.
'of time' acts as a link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for sagest that I've seen before include "Gas set (anag.)" , "Wisest" , "Most wise and prudent" , "Most discerning" , "Extremely clever" .)