Magic

adj. 1. As yet unexplained, or too complicated to explain; compare automagically and (Arthur C.) Clarke's Third Law:

"Any sufficiently advanced technology is indistinguishable from magic."

"TTY echoing is controlled by a large number of magic bits."

"This routine magically computes the parity of an 8-bit byte in three instructions."

2. Characteristic of something that works although no one really understands why (this is especially called black magic).

3. [Stanford] A feature not generally publicized that allows something otherwise impossible, or a feature formerly in that category but now unveiled.

Compare deep magic, wizardly, heavy wizardry.