### Clue: First one sincere, though huge middle revealed when shirt removed (9)
### Answer: INAUGURAL 
 ### Explanation: Definition: First
  I(Roman numeral for "one") + "natural"(sincere/not faked like some airline attendant's smile) **with 2 middle letters of**(… middle) "huge" ***replacing***(revealed when … removed) "t"(short for "tee shirt").