Bit of wood glue (5)
I believe the answer is:
stick
This clue is a double definition.
'bit of wood' is the first definition.
(a stick is a bit of wood from a tree)
'glue' is the second definition.
(to stick with glue)
(Other definitions for stick that I've seen before include "heavy criticism" , "Gear lever; adhere" , "Staff - criticism" , "School punishment once" , "Rod" .)