More invention welcomed by chateau topiarist (6)
I believe the answer is:
utopia
'more invention' is the definition.
(I've seen this in another clue)
'welcomed by chateau topiarist' is the wordplay.
'welcomed by' indicates a hidden word.
'UTOPIA' can be found hidden inside 'chateau topiarist'.
(Other definitions for utopia that I've seen before include "More's imaginary state" , "Sir Thomas More's ideal society" , "A perfect place according to Thomas More" , "Imaginary place where everything is perfect" , "Imaginary ideal place" .)