Beastly female gets sir excited (7)
I believe the answer is:
tigress
'beastly female' is the definition.
The answer and definition can be both animals as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'gets sir excited' is the wordplay.
'excited' indicates an anagram.
'gets'+'sir'='getssir'
'getssir' with letters rearranged gives 'TIGRESS'.
Can you help me to learn more?
(Other definitions for tigress that I've seen before include "Wild cat (female)" , "Female wildcat" , "dangerous animal" , "A beastly female" , "Female striped cat" .)