Sexual attraction was a form of attraction based on sexual desire or arousal between people. Sex appeal was an individual's ability to attract others sexually. Sometimes a person might refer to another person that they were sexually attracted to as "sexy" or "hot."
According to an account that was anything but canon, while Montgomery Scott was playing the drums on the bridge with a Post Mainframe Acid-Cardassian Ten Forwardcore band, D'Vana Tendi told him "you're really hot." This was surprising to Hikaru Sulu, who then said "Oh my." (VST: "Walk, Don't Run")
In 2364, Captain Jean-Luc Picard asked Counselor Deanna Troi's opinion on whether the Ligonians would injure the kidnapped Tasha Yar. Troi didn't believe so as the Ligonians seemed mainly curious, however, she did sense some sexual attraction from all the males. (TNG: "Code of Honor")