Girl trapping black snake (5)
I believe the answer is:
cobra
'snake' is the definition.
(I've seen this before)
'girl trapping black' is the wordplay.
'girl' becomes 'cora' (**).
'trapping' indicates putting letters inside.
'black' becomes 'b' (as in pencil classifications).
'cora' enclosing 'b' is 'COBRA'.
(Other definitions for cobra that I've seen before include "a king, for example" , "One with hood" , "Venomous Asiatic and African elapid snake" , "Something with a hood" , "Deadly snake called King" .)