Asp or adder
I believe the answer is:
I believe this is a double definition.
'asp' is the first definition.
(thesaurus)
'adder' is the second definition.
(thesaurus)
(Other definitions for snake that I've seen before include "Move sinuously" , "Limbless reptile" , "Carnivorous reptile" , "Long slender reptile" , "Serpent" .)