Venomous British reptile (5)
I believe the answer is:
adder
(Other definitions for adder that I've seen before include "Something you have to reckon with" , "Venomous sort" , "venomous creature" , "poisoner" , "One creature" .)
I believe the answer is:
adder
(Other definitions for adder that I've seen before include "Something you have to reckon with" , "Venomous sort" , "venomous creature" , "poisoner" , "One creature" .)