Wonderful guess (6)
I believe the answer is:
divine
This clue is a double definition.
'wonderful' is the first definition.
(I've seen this before)
'guess' is the second definition.
(divining is a kind of guessing)
(Other definitions for divine that I've seen before include "Predict" , "clergyman" , "Like a god; delightful" , "Sacred; excellent" , "Sacred; delightful" .)