Roguish leader missing from demo (4)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
arch
'roguish' is the definition.
(I've seen this in another clue)
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(Other definitions for arch that I've seen before include "Structural curve" , "in short, is out of date" , "Curvature" , "Knowing, sly" , "Consciously or affectedly playful - under a bridge?" .)