Reference book has uterus misspelled (9)
I believe the answer is:
'reference book' is the definition.
(I know that thesaurus is a type of wordbook)
'has uterus misspelled' is the wordplay.
'misspelled' indicates anagramming the letters (I've seen this in other clues).
'hasuterus' with letters rearranged gives 'THESAURUS'.
(Other definitions for thesaurus that I've seen before include "Reference book" , "treasury" , "lists?" , "work we may refer to" , "Book of words with synonyms, antonyms etc" .)