Lethal

//ˈliː.θəl// adj, noun

adj, noun ·Moderate ·College level

Definitions

Noun
  1. 1
    Any weapon that causes death.
  2. 2
    One of the higher alcohols of the paraffine series obtained from spermaceti as a white crystalline solid. uncountable
  3. 3
    An allele that causes the death of the organism that carries it.
Adjective
  1. 1
    Of, pertaining to, or causing death; deadly; mortal; fatal.

    "Whether modern, industrial man is less or more warlike than his hunter-gatherer ancestors is impossible to determine. The machine gun is so much more lethal than the bow and arrow that comparisons are meaningless."

Adjective
  1. 1
    of an instrument of certain death wordnet

Synonyms

All synonyms
fatalmurderousbalefulbanefulbrutalcalamitous

Example

More examples

"Improper grounding can make a microphone lethal to touch. Several singers have actually died this way."

Etymology

Etymology 1

Learned borrowing from Latin lētālis (“deadly, mortal, fatal”), improperly written lēthālis, from lētum (“death”), improperly written as lēthum, from a supposed connection with Ancient Greek λήθη (lḗthē, “oblivion, forgetfulness”).

Etymology 2

Abbreviation of “lauric acid ethereal salt”, so called because it occurs in the ethereal salt of lauric acid.

Related phrases

coat color dilution lethalless-lethalless-than-lethallethal allelelethal chamberlethal congenital contracture syndromelethal doselethal genelethal injectionlethal timelethal white syndromelethal yellowing

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Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.