A wild hornet - not the first of its kind (7)
I believe the answer is:
another
'not the first of its kind' is the definition.
I can't judge whether this definition defines the answer.
'a wild hornet' is the wordplay.
'wild' indicates an anagram.
'hornet' anagrammed gives 'nother'.
'a'+'nother'='ANOTHER'
Can you help me to learn more?
(Other definitions for another that I've seen before include "second" , "A further (item)" , "encore?" , "On earth (anag.)" , "Additional, one more" .)