capitate(capital)->say head of country->so decapitate means dehead or behead
de = down, cap = head => "decapitate" then means "cut that head down"
de-cap= behead... also it rhymes with decapacitate... which means to kill
DE CAP IT ATE had a BE(e's)HEAD in it(sry if it is too silly and wierd).
decapitate : lets make it like a vampire ne [the]de cap [rakhane ki jaga head] ,and it [cap][kha liya]ate
decapitate(the +cap+ate) the cap is ate with head by rhino ,so man is behead
decapitate-> take the head with the cap