Ideal sort of prefect (7)
I believe the answer is:
perfect
'ideal' is the definition.
(similar in meaning)
'sort of prefect' is the wordplay.
'sort of' indicates anagramming the letters.
'prefect' anagrammed gives 'PERFECT'.
(Other definitions for perfect that I've seen before include "Ideal, flawless" , "Past tense; ideal" , "Without blemish" , "Faultless" , "Ideal, without flaw" .)