1905, from sex (n.) + -y (2). Originally "engrossed in sex;" sense of "sexually attractive" is 1923, first in reference to Valentino. An earlier word in this sense was sexful (1898). Related: Sexier; sexiest.
Very appealing; exciting; desirable; stimulating: Acid rain is politically sexy, but it hasn't half the allure of jobs(1970+)
The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D. Copyright (C) 2007 by HarperCollins Publishers. Cite This Source