### Clue: The editor sent back excellent piece of writing about sex (8,7)
### Answer: DEFINITE ARTICLE 
 ### Explanation: Definition: The 
 **Reversal of**(… sent back) ED(abbrev. for "editor") + FINE(excellent) ARTICLE(a piece of writing, in the newspaper, say) **containing**(about) IT(a euphemistic term for sexual intercourse).
Answer: An example of which is "the".