knife -- (edge tool used as a cutting instrument; has a pointed blade with a sharp edge and a handle)
knife -- (a weapon with a handle and blade with a sharp point)
tongue, knife -- (any long thin projection that is transient; "tongues of flame licked at the walls"; "rifles exploded quick knives of fire into the dark")
Overview of verb knife
The verb knife has 1 sense
knife, stab -- (use a knife on; "The victim was knifed to death")