Calculating type's more pathetic when losing head (5)
I believe the answer is:
adder
This clue might be a double definition.
'calculating type's more' is the first definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
'pathetic when losing head' is the second definition.
The definition and answer can be both animals as well as being singular nouns.
Maybe they are linked in a way I don't understand?
Can you help me to learn more?
(Other definitions for adder that I've seen before include "Sliding" , "Venomous type" , "a poisonous type" , "calculator?" , "danger in the countryside" .)