Fancy pants + smarty pants = farty pants! Tada!
It could also be macy pants. As in pants you bought from macy’s. Sometimes they have really good sales on pants, but I usually shop at JC penny’s.
Or maybe they’re pants that Macy Gray used to own or designed or something.
Why not “smancy pants”?
They went out of style years ago.
They only do upscale boutique stuff now.
Fancy Smancy