Answer: Still, kill, ill.
As an illustration of "Decapitation" of words by syllables rather than by letters, we give the following:—
My whole is significant of dissolution.
Behead me, and I am a school exercise significant of construction.
Behead me again, and I denote the place attained by the exercise.
Answer: Decomposition, composition, position.
My whole is unbearable.
Beheaded, I am bearable.
Again beheaded, I am easily moved.
Once more beheaded, I remain a solid piece of furniture.