Straight up (bartending) in the context of "Rum"

Rum is a liquor made by fermenting and then distilling sugarcane molasses or sugarcane juice. The distillate, a clear liquid, is often aged in barrels of oak. Rum originated in the Caribbean in the 17th century, but today it is produced in nearly every major sugar-producing region of the world.

Rums are produced in various grades. Light rums are commonly used in cocktails, grog, or toddy, whereas "golden" and "dark" rums, once typically drunk straight (U.S. English) or neat (Commonwealth English), iced ("on the rocks"), or in cooking, are now commonly drunk with mixers. Premium rums are made to be consumed either straight or iced.