WordReference Random House Learner's Dictionary of American English © 2026knife /naɪf/USA pronunciation
n., pl. knives /naɪvz/USA pronunciation v., knifed, knif•ing. n. [countable]
- an instrument for cutting, made of a sharp-edged metal blade fitted with a handle:steak knives.
- a knifelike weapon;
The man was dead, with a knife sticking out of him.
v.
- to cut, stab, etc., with a knife:[~ + object]had been knifed and left to die.
- to move through something with or as if with a knife:[no object]The ship knifed through the water.
Idioms
- knife (someone) in the back, to attempt to defeat, weaken, or ruin someone in a secret or dishonest way.
WordReference Random House Unabridged Dictionary of American English © 2026knife
(nīf ),USA pronunciation n., pl. knives (nīvz),USA pronunciation v., knifed, knif•ing. n.
- an instrument for cutting, consisting essentially of a thin, sharp-edged, metal blade fitted with a handle.
- a knifelike weapon;
dagger or short sword.
- any blade for cutting, as in a tool or machine.
- Idioms under the knife, in surgery;
undergoing a medical operation:The patient was under the knife for four hours.
v.t.
- to apply a knife to;
cut, stab, etc., with a knife.
- to attempt to defeat or undermine in a secret or underhanded way.
v.i.
- to move or cleave through something with or as if with a knife:The ship knifed through the heavy seas.
- bef. 1100; Middle English knif, Old English cnīf; cognate with Dutch knijf, German Kneif, Old Norse knīfr
knife′like′, adj.
knif′er, n.
Collins Concise English Dictionary © HarperCollins Publishers::
knife / naɪf/ ( knives / naɪvz/)- a cutting instrument consisting of a sharp-edged often pointed blade of metal fitted into a handle or onto a machine
- a similar instrument used as a weapon
- under the knife ⇒ undergoing a surgical operation
(transitive)- to cut, stab, or kill with a knife
- to betray, injure, or depose in an underhand way
Etymology: Old English cnīf; related to Old Norse knīfr, Middle Low German knīfˈknifeˌlike
'the knife' also found in these entries (note: many are not synonyms or translations):