Amount of glue? (4)
I believe the answer is:
size
This clue is a double definition.
'amount' is the first definition.
(I've seen this before)
'glue?' is the second definition.
(thesaurus)
'of' acts as a link.
(Other definitions for size that I've seen before include "gelatinous mixture" , "Physical magnitude" , "mass" , "Amount" , "Dimension" .)