### Clue: What a pretentious Radio 3 presenter would do? (3,2,4)
### Answer: PUT ON AIRS 
 ### Explanation: Definition: What a pretentious Radio 3 presenter would do
 Cryptic defn: Reference to BBC Radio 3, a station whose staple is highbrow classical music, and to any of its presenters who would literally put on (broadcast over the air) classical airs. Which, if taken figuratively, would make him/her a pretentious ass.