deadly

The word “deadly” means capable of causing death. In plain terms, able to kill, or (informally) extremely something — usually extremely boring or extremely skilled.

“Deadly” is pronounced DEHD-lee (/ˈdɛdli/ in IPA).

Here is “deadly” used in a sentence: “The snake's venom is deadly if left untreated.”

Depending on how it is used, “deadly” can be an adjective and an adverb.

The word “deadly” comes from Old English. From Old English deadlic, built from dead plus -lic (the ancestor of -ly), literally "death-like".

“Deadly” is a fairly common word in modern English, usually learned at around the B1 level.

“Deadly” has 3 distinct senses listed in this dictionary. The most common is: capable of causing death.

"Deadly" means capable of causing death, as in a deadly poison. "Deathly" means resembling death or suggesting it, as in "deathly pale" or "deathly silence," and does not mean actually able to kill.

Both mean able to cause death, and they often overlap. "Lethal" tends to sound more technical or clinical, as in "a lethal dose," while "deadly" is more general and can also mean extremely effective, as in "deadly accurate."

"Deadly" describes something with the potential to cause death, such as a deadly weapon, before any harm has happened. "Fatal" usually describes something that actually did cause death, such as a fatal accident.