noun

• (uncountable, informal) Any semi-solid or liquid substance; especially one that is sticky, gummy or slippery, unpleasant, and of vague or unknown composition, such as slime or semen.
  "I stepped in some goo and had a terrible time getting the sticky stuff off my shoes."
• (figuratively) Excessive, showy sentimentality.
  "[…] To be really human is probably to be unavoidably sentimental and naive and goo-prone and generally pathetic, is to be in some basic interior way forever infantile, some sort of not-quite-right-looking infant dragging itself anaclitically around the map, with big wet eyes and froggy-soft skin, huge skull, gooey drool."

verb

• (transitive) To apply goo to something.
  "They gooed their hair with some fragrant styling product."

verb

• (intransitive) To produce baby talk.
  "The baby gooed while daddy made sappy faces at it."

verb

• (Northern England, West Midlands, Scotland) Pronunciation spelling of go.
  "Well, then, things are settled, an' I'll goo an' finish yond pigs off," said my new employer, rising from his chair, and flapping his crush hat upon his head as if he was killing flies."