Yours truly, a snooty type, reviewed Japanese art (6)
I believe the answer is:
bonsai
'japanese art' is the definition.
(I've seen this before)
'yours truly a snooty type reviewed' is the wordplay.
'yours truly' becomes 'i'.
'snooty type' becomes 'snob' (I've seen this before).
'reviewed' says the letters should be written backwards.
'i'+'a'+'snob'='iasnob'
'iasnob' back-to-front is 'BONSAI'.
(Other definitions for bonsai that I've seen before include "Japanese craft of growing dwarf trees" , "Small tree" , "stunted growth" , "Japanese craft of growing miniature trees" , "Tiny Japanese tree" .)