### Clue: Working sort first off with stamps welcoming latest of clientele? (10)
### Answer: POSTMASTER 
 ### Explanation: Definition: Working sort
 **Anagram of**(Working) [ "sort" **minus ****its 1st letter**(first off) **plus**(with) STAMPS] **containing**(welcoming) **last letter of**(latest of) "clientele".
Defn:  One whose work involves selling stamps to a post office's clientele?  I could be wrong with this.