A sting is a sharp-pointed organ or instrument that wounds by puncturing. Scripture speaks of the sting of an adder and of scorpions, and also uses the term for a goad or spur.
In the biblical image, death is portrayed as a deadly creature whose sting is sin. Death is powerless through sin, and when sin is conquered, the fear of death is removed. The same Greek word can also describe an instrument used to excite fear.