(n): the trace of a point whose direction of motion changes
(n): a curved bony structure supporting or enclosing organs (especially the inner sides of the feet)
(n): any structure created by the skeleton of an organism
(n): a passageway under a curved masonry construction
(n): something that provides access (to get in or get out)
(n): (architecture) a masonry construction (usually curved) for spanning an opening and supporting the weight above it
(n): a thing constructed; a complex entity constructed of many parts
(adj): (used of behavior or attitude) characteristic of those who treat others with condescension
(adj): vs. inferior) -- (of or characteristic of high rank or importance
(adj): prenominal) -- (expert in skulduggery
(adj): vs. unskilled) -- (having or showing or requiring special skill
(adj): naughtily or annoyingly playful
(adj): vs. unplayful) -- (full of fun and high spirits
(v): form an arch or curve
(v): form a curve
"He was also known for weaving together seemingly unrelated themes in an arch, self-deprecating way that helped break down the image of the critic as an all-knowing figure who wrote from atop a pedestal."
The New York Times, October 3, 2007, Herbert Muschamp Obit
I like the sense of mischievous
Also, Professor Moriarty's way off the Holodeck.
The secondary definition is especially interesting:
1. playfully roguish or mischievous: an arch smile.
2. cunning; crafty; sly.