Possibly signed drawing (6)
I believe the answer is:
design
'drawing' is the definition.
(design is a kind of drawing)
'possibly signed' is the wordplay.
'possibly' indicates an anagram.
'signed' anagrammed gives 'DESIGN'.
(Other definitions for design that I've seen before include "Plan, drawing" , "Plan, blueprint" , "Develop or prepare a plan" , "Preliminary sketch or plan" , "Drawing before an object is made" .)