lethally

adjective

1. of, relating to, or causing death; deadly; fatal: a lethal weapon; a lethal dose.
2. made or carried out to cause death: a lethal chamber; a lethal attack.
3. causing great harm or destruction: The disclosures were lethal to his candidacy.

adjective

1. able to cause or causing death
2. of or suggestive of death

adj.1580s, from Late Latin lethalis, alteration of Latin letalis “deadly, fatal,” from letum “death,” of uncertain origin. Form altered in Late Latin by association with lethe hydor “water of oblivion” in Hades in Greek mythology, from Greek lethe “forgetfulness.” adj.

1. Capable of causing death.
2. Of, relating to, or causing death.