Sexyとは、
1. concerned predominantly or excessively with sex; risqué:
例 a sexy book.
2. sexually interesting or exciting; radiating sexuality:
例 the sexiest dancer on stage.
3. excitingly appealing; glamorous:
例 a sexy sports car.
人を「sexy」と呼ぶ場合は99.999%No.2の意味です。