What does it mean to dream about knife?
A knife tends to point to a cut you need or fear, a separation, a sharp word, or a defence, depending on who wields it and how it feels.
Four ways to read it
Each reading below comes from a named tradition and a cited source, so you can see where it came from and decide what fits your dream.
Freud
Freud read the knife as a phallic and aggressive image, the instrument of a wish to wound, sever, or penetrate.
After Freud, The Interpretation of Dreams (Brill trans., 1913), public domain.Jung
Jung would see the power to divide and discriminate, to cut away what no longer serves, or the threat of being cut off.
Jungian concept (our summary).Modern
Continuity ties knives to waking conflict, betrayal, or a decision to end something. The threat-simulation idea fits an attack.
Threat-simulation theory (our summary).Mythological
The sacrificial blade runs through myth and rite, from Abraham's knife to the sacred sickle, marking the moment of severance and offering.
Rosmerta Publishing editorial synthesis (after Frazer; Bulfinch).