Creative doctor a strict one (8)
I believe the answer is:
artistic
'creative' is the definition.
(I've seen this in another clue)
'doctor a strict one' is the wordplay.
'doctor' indicates anagramming the letters.
'one' becomes 'i' (Roman numeral).
'a'+'strict'+'i'='astricti'
'astricti' anagrammed gives 'ARTISTIC'.
(Other definitions for artistic that I've seen before include "Satisfying aesthetic standards" , "Naturally creative" , "cultivated" , "Skilled at painting, music etc" , "Having a creative imagination" .)