Some most extraordinary words (4)
I believe the answer is:
text
'words' is the definition.
(thesaurus)
'some most extraordinary' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'TEXT' is hidden in the letters of 'most extraordinary'.
(Other definitions for text that I've seen before include "Book set for exam" , "Printed or written words" , "Send a written message by phone" , "Book or play prescribed for study" , "Sermon basis" .)