"___ perfect world ..." (3)
'perfect world' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for utopia that I've seen before include "Sir Thomas Moore's perfect society" , "Perfect world?" , "Imaginary ideal place" , "More's imaginary state" , "Impracticable state of perfection" .)
(Another definition for ina that I've seen is " Girl".)