Killing someone in a dream horrifies the dreamer more than any tradition it's brought to — all three read it as ending, not evil: in the West a part of life being forcibly finished, in the East a matter cut off at the root, and in Ibn Sirin's corpus, startlingly, killing often reads toward prevailing.
Three readings
In Western psychology · Jungian
The dream-killer is almost never murderous — they are decisive. Psychologically, killing in a dream is the mind's strongest verb for 'make this stop': a role, an attachment, an aspect of yourself (the victim often carries a trait you're done with). Guilt on waking is nearly universal and is simply the cost of the metaphor. The productive question is never 'am I violent?' but 'what have I been trying to end politely that the psyche just ended plainly?'
The Eastern entries read killing toward severance: something is being ended at the root — a tie, a habit, a dispute — and the dream stages the ending as a deed because half-measures haven't worked. Who died carries the reading: a stranger, some unnamed obstacle; a known face, what that person represents in your account books. The counsel is unsentimental: something in your life requires a clean ending you keep performing only in sleep.
The corpus contains one of dreaming's great inversions: killing in a dream was often read toward gaining the upper hand — the classical entries link slaying an adversary with prevailing over him, and some read the victim as gaining long life. No guilt attaches to the dreamer of such a dream in the tradition; dreams are not deeds. As meaning: a contest in your life is resolving in your favor, or a matter is being decisively closed — see that the closing stays just.
No — and this may be the dream with the widest gap between how it feels and what it means. Every tradition reads dream-killing as ending, severance, or prevailing; none reads it as character. Dreams use the strongest available verbs for ordinary inner work.
I killed someone I love in the dream — why?
Usually you ended what they represent — a dynamic, a dependence, an old version of the relationship — not the person. These dreams often precede healthy renegotiations: something between you needed to die so the rest could live.
What does hiding the body mean?
The cover-up is the tell: an ending you've performed but not owned — a decision made inwardly and not yet announced, a boundary drawn in secret. The dream says the deed is done; daylight is waiting for the honesty.
This is the general reading. Your dream is specific.