Messy stuff (3)
'messy stuff' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for goo that I've seen before include "Sticky and slimy stuff" , "Sticky stuff or sickly sentiment" , "Sticky gunge" , "Sticky or slimy substance" , "Sentimentality (sl.)" .)
'messy stuff' is the definition.
(I've seen this in another clue)
This is all the clue.
(Another definition for glop that I've seen is " Bland mushy food".)