Lethal

Part of speech: adjective

Pronunciation: /ˈliː.θəl/

Definitions

1. Having the ability to result in fatal outcomes or serious injury
2. Possessing the power to end life or cause substantial damage to health
3. Capable of causing death or very serious physical injury

Etymology: The Latin root of "lethal" is "lētum," meaning "death," but the spelling we see today is the product of a mistake. Classical Latin wrote "lētālis," yet scholars in the Renaissance, believing the word was linked to the Greek "lḗthē," meaning "oblivion" or "forgetfulness," altered it to "lēthālis" with an h. The Greek link was never real. The h was an error that later writers copied, and it is why English "lethal" carries an h that the original Latin never had. The English adjective is a learned borrowing from Latin, so it entered the language through scholarly and technical writing rather than everyday speech. Its core meaning stayed close to the Latin: something capable of causing death. Over time the sense widened so that the word now also covers serious injury, as in a "lethal weapon" or "lethal dose," where the outcome is grave even when death is not certain.

Synonyms: deadly, fatal, mortal, perilous, destructive

Antonyms: harmless, safe, beneficial, nonlethal, innocuous