Venomous spider (5,5)
I believe the answer is:
black widow
'venomous spider' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for black widow that I've seen before include "American spider, the female of which eats her mate" , "venomous creature" , "Leggy creature" , "she's usually the bereaver" , "Poisonous spider" .)