|Origin:||lethalis, from lethum 'death', from letum (influenced by Greek lethe; LETHARGIC)|
causing death, or able to cause death [↪ fatal]:
a lethal dose of heroin
death by lethal injection
a lethal cocktail of drink and pills
These chemicals are lethal to fish.
likely to be powerful or dangerous - often used humorously:
They were all drinking lethal amounts of tequila!
Higher taxes and higher inflation were a lethal combination.