Intelligently analytical and clear-thinking (8)
I believe the answer is:
incisive
'intelligently analytical and clear-thinking' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for incisive that I've seen before include "Of speech, sharp and clear" , "(Of action) quick, direct" , "Clear and penetrating, as of speech" , "Piercing" , "Clear and cutting" .)