deleter-, deleteri- +

(Greek: to harm, to hurt, to injure, to damage, to destroy; destroyer; harmful)

deleterious
1. Having a harmful effect; injurious: "Face it, there is obviously a deleterious effect from smoking."
2. Having a harmful or damaging effect on someone or something.
3. Etymology: from Middle Latin deleterius; from Greek deleterios, "noxious", from deleter, "destroyer", from deleisthai, "to hurt, to injure".
deleteriously
Characterized by being harmful, often in a subtle or unexpected way.
deleteriousness
A condition in which something causes moral or physical injury; perniciousness, harmfulness, destructiveness; noxiousness.
deletery
Destructive; poisonous; that which destroys.