Irene gets excited about many a fur (6)
I believe the answer is:
ermine
'a fur' is the definition.
(I know that ermine is a type of fur)
'irene gets excited about many' is the wordplay.
'gets excited' is an anagram indicator.
'about' is an insertion indicator.
'many' becomes 'm' (Roman numeral for a thousand).
'irene' with letters rearranged gives 'erine'.
'erine' going around 'm' is 'ERMINE'.
(Other definitions for ermine that I've seen before include "special trimmings" , "Regal fur" , "In mere strange fur" , "White-coated stoat" , "White fur of stoat" .)