Somewhat polite, rational, well-read types (8)
I believe the answer is:
literati
'well-read types' is the definition.
(I've seen this in another clue)
'somewhat polite rational' is the wordplay.
'somewhat' says the answer is hidden in the clue.
'LITERATI' can be found hidden inside 'polite rational'.
(Other definitions for literati that I've seen before include "Literary intelligentsia" , "Learned people, men of letters" , "scholars" , "The well-read intelligentsia" , "Learned, well-read people" .)