Green’s Dictionary of Slang

1. (orig. media) used to describe anything that pulls in audiences, readers etc, thus usu. violence, disaster, scandal etc.

1978		Harper’s Mag. May 34: The farmers are not a sexy protest group [...] They just can’t drum up the kind of sympathy here that, say, the blacks and the feminists can.
1990		S. Morgan Homeboy 215: The more homicides a prison successfully prosecutes, the sexier a warden’s bonuses.
2000		Indep. on Sun. Rev. 20 Feb. 69: This makes the films less sexy than Dinosaurs, but more scientific.

2. (US) used to describe anything very appealing.

1999

K. Sampson Powder 62: They’d ordered two hundred seven-inch white-label vinyl EPs, sexy little things to mail out to radio, press and those with influence.

3. used of anything or anybody ‘clever’ or ‘smart’.

1990		S. Morgan Homeboy 73: Face down! And nothing sexy, I’ll dust ya, I swear you’ll die.
1992		Eble Campus Sl. Apr. 8: sexy – good, suave, sophisticated: ‘Adam thinks he’s too sexy to go to the formal’.