rum (n.) Look up rum at Dictionary.com
"liquor from sugar cane or molasses," 1650s, originally rumbullion (1651), rombostion (1652), of uncertain origin, perhaps from rum (adj.).
The chiefe fudling they make in the Island [i.e. Barbados] is Rumbullion alias Kill-Devill, and this is made of suggar cane distilled, a hott, hellish and terrible liquor. [1651]
The English word was borrowed into Dutch, German, Swedish, Danish, Spanish, Portuguese, Italian, French, and Russian. Used since 1800 in North America as a general (hostile) name for intoxicating liquors. Rum-runner "smuggler or transporter of illicit liquor" is from 1919.
rum (adj.) Look up rum at Dictionary.com
"excellent," 1560s, from rome "fine" (1560s), said to be from Romany rom "male, husband" (see Romany). A very common 16c. cant word, by 1774 it had come to mean "odd, strange, bad, spurious," perhaps because it had been so often used approvingly by rogues in reference to one another. This was the main sense after c.1800.