Visionary cities laid out (10)
I believe the answer is:
idealistic
'visionary' is the definition.
(I've seen this before)
'cities laid out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'cities'+'laid'='citieslaid'
'citieslaid' is an anagram of 'IDEALISTIC'.
(Other definitions for idealistic that I've seen before include "Striving for perfection" , "Utopian" , "Visionary" , "Seeking the best" , "High-minded - italicised (anag)" .)