This is the 4577th most frequent French word.
meurtrier
"Meurtrier" means "murderer" in English.
In this sentence, 'meurtrier' is used as a noun referring to a person who commits murder.
Le meurtrier a été arrêté par la police.
The murderer was arrested by the police.
Here, 'meurtrier' is an adjective describing something that causes death.
Le coup de poignard était meurtrier.
The stab wound was deadly.
In this usage, the word 'meurtrier' is an adjective characterizing the event as causing harm or death.