from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Slang A thick messy substance, such as sludge.
from the GNU version of the Collaborative International Dictionary of English
- n. any thick messy substance.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. any thick, viscous matter
Possibly g(oo) + (m)uck.(American Heritage® Dictionary of the English Language, Fourth Edition)