Engineer Jailbait

Someone who has been coding since a very early age and is employed at a large company or startup. They are younger than 18, but seem much older given the vast depth of their knowledge.

Julie: That guy Kumar is kind of cute.
George: Woah, I'd stay away from him if I was you, he's 17 and engineer jailbait.
Julie: Good thing you told me. I dodged a serious bullet, but man he's such a tease.