Heavyweight
High-overhead;
baroque; code-intensive; featureful, but costly.
Especially used of communication protocols, language designs, and any sort of implementation in which maximum generality and/or ease of implementation has been pushed at the expense of mundane considerations such as speed, memory use and startup time.
Emacs is a heavyweight editor;
X is an *extremely* heavyweight window system.
This term isn't pejorative, but one hacker's heavyweight is another's
elephantine and a third's monstrosity.
Opposite: "lightweight".
Usage: now borders on technical especially in the compound "heavyweight process".