/aw-toh-maj'i-klee/ or /aw-toh-maj'i-k*l-ee/ Automatically, but in a way that, for some reason (typically because it is too complicated, or too ugly, or perhaps even too trivial), the speaker doesn't feel like explaining to you.

E.g. "The C-INTERCAL compiler generates C, then automagically invokes cc to produce an executable."

See magic.

[Jargon File]