Watery or papery (4)
I believe the answer is:
thin
I believe this is a double definition.
'watery' is the first definition.
(similar in meaning)
'papery' is the second definition.
(similar in meaning)
(Other definitions for thin that I've seen before include "Skinny" , "With little thickness" , "Lean; make (plants) less crowded" , "Insubstantial" , "Lacking substance; not dense" .)