Various things trimmed slender ornate hatstand (4,3,4)
I believe the answer is:
this and that
'various things' is the definition.
'trimmed slender ornate hatstand' is the wordplay.
'trimmed' means to remove the last letter (the final letter is trimmed off).
'slender' becomes 'thin' (similar in meaning).
'ornate' indicates an anagram (an unusual or complex form of the letters).
'thin' with its last letter taken off is 'thi'.
'hatstand' with letters rearranged gives 'sandthat'.
'thi'+'sandthat'='THIS AND THAT'
(Other definitions for this and that that I've seen before include "Unspecified things" , "One thing and another" .)