Vision: Seeing your own decapitation: either illness or shame and embarrassment.
If you are decapitating somebody else: you arc possibly the winner in a conflict or a legal argument. Watching someone you know being decapitated: you are losing a person you love. Watching a stranger being decapitated: you might either defeat an adversary or create new enemies. See Execution, Head.
Depth Psychology: Decapitation is a sign that you are revising your present attitude about a specific event. Are you being ruled too much by your head? Maybe you should start trusting your intuition more and living accordingly!... Dreamers Dictionary