### Clue: Instruct headless knights over vacuous foolery (5)
### Answer: EDIFY 
 ### Explanation: Definition: Instruct
 **1st letter deleted from**(headless) "Jedi"(members of the knightly order in the Star Wars films) **placed above**(over, in a down clue) **1st and last letters deleted from**(vacuous) "foolery".