Decapitation was the act of removing someone's head.
Blon Fel-Fotch Passameer-Day Slitheen killed Mr. Cleaver by decapitating him. While disguised as a human, she claimed that he slipped on "a very icy patch". (DW: Boom Town)
Time Lords could still regenerate after being decapitated. Cavisadoratrelundar was decapitated and only killed after being stabbed in both her hearts. (EDA: The Shadows of Avalon)
A suicide bomber that was still living (due to Miracle Day) even after blowing himself up was still conscious even after his head was detached. (TW: The New World)
Members of the Order of the Headless were decapitated in their initiation. Their body's and heads remained mobile, even after their heads had rotted into skulls. (DW: A Good Man Goes to War, (DW: The Wedding of River Song))
