What does goo mean?
Goo is an informal noun for a soft, sticky, viscous substance, such as slime, melted residue, or a messy spill. It is also used figuratively when the exact nature of something is unknown, especially when the material seems unpleasant or suspicious: the phrase "mysterious goo" captures this use. The word frequently appears in contexts involving children, messes, food, paint, or unidentified residues, so it can sound playful, humorous, or mildly disgusted. Although it can describe genuinely sticky material, it is less precise than terms such as "slime," "sludge," or "adhesive" because "goo" emphasizes the impression of gooeyness rather than a scientific category. Goo is recognizable in both British and American English and belongs mainly to informal vocabulary. Its vagueness makes it especially useful for describing substances that resist easy identification.
nounA soft, sticky, viscous substance. Informally, it can also refer to any unclear, messy, or unpleasant material.
- A soft, sticky, viscous substance.
- An unspecified or unidentifiable messy material, often regarded as unpleasant or disgusting.
"There was a blob of goo on the floor after the paint can tipped over."
"The children were covered in colorful goo after playing with the paint."
"I could not tell whether the substance on the shelf was food, glue, or some kind of mysterious goo."
The plural is possible but uncommon, since goo is often used as a mass noun.
"Several small goos had formed near the drain."
Goo is a distinctly modern word for a very familiar substance: its first known uses date to the early 20th century, but its ultimate origin remains mysterious.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does goo come from?
Goo is an English word recorded from the early 20th century. Although its development can be compared with forms such as gooey, its ultimate origin is uncertain, and no reliable group of cognate words can be securely identified.
Related word forms
How goo is actually used
Goo is informal and often has a playful, childish, or mildly disgusted tone. It is common in both British and American English, especially in speech.
Easily confused with goo
Glue is an adhesive substance used to join materials, whereas goo is a general informal term for a sticky or messy substance.
Gunk usually suggests dirty, unappealing residue or miscellaneous rubbish, while goo more specifically suggests a soft, sticky material.