Wildly remonstrated with pet shop (10,5)
I believe the answer is:
department store
'shop' is the definition.
(thesaurus)
'wildly remonstrated with pet' is the wordplay.
'wildly' indicates an anagram.
'with' says to put letters next to each other.
'remonstrated' put after 'pet' is 'petremonstrated'.
'petremonstrated' with letters rearranged gives 'DEPARTMENT STORE'.
(Other definitions for department store that I've seen before include "Big shop" , "large shop" , "Building" , "shopping centre" , "place on the high street" .)