Bow demo leader cancelled (4)
I believe the answer is:
arch
'bow' is the definition.
(both can mean to curve)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for arch that I've seen before include "Curved span" , "Roguish - chief - supporter" , "Chief - supporter - cunning" , "Supporting structure" , "Affectedly playful (4)" .)