Something that's juicy is so moist that it's dripping with juice. There is nothing quite like eating a juicy, ripe peach in the summer.
Perfect peaches and oranges and pears should be juicy when you bite into them. Aside from fruit, people also commonly describe meat as juicy. A story might be figuratively juicy too, if it's full of intriguing, gossipy details: "Did you read about that juicy scandal in the mayor's office?" Juicy comes from the Old French jus, "juice," with the Latin root ius, "broth, sauce, or juice."