Slang A thick messy substance, such as sludge.(noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "guck" in a sentence
"The guck is gone from the air, the streets are cleaned, and, if things are really wet and cold, the local mountains gets snow."
"And wash your hands all the time -- all the time -- because you just never know what kind of guck (ph) is out there."
"Here is a nest for a bird, ( "guck" all birds are ducks)"