Rough plan from special executioner (6)
I believe the answer is:
sketch
'rough plan' is the definition.
(sketch can mean a vague plan or idea)
'special executioner' is the wordplay.
'special' becomes 'S' (common abbreviation as in Special Air Service).
'executioner' becomes 'ketch' (Jack Ketch was a 17th-century executioner).
's'+'ketch'='SKETCH'
'from' acts as a link.
(Other definitions for sketch that I've seen before include "Unfinished drawing" , "Delineate" , "Short humorous scene" , "'A rough, quick drawing (6)'" , "Small sailing boat" .)