1. In Costa Rica, a sugar cane liquor branded under the name Cacique. Used for shots, mixed drinks, and even cooking.
2. In Costa Rica and Colombia, a generic name for any and all booze. Note however that guaro is a particular liquor as described above. Similar to the usage of the word "coke" for all softdrinks in the midwestern US.
3. In Colombia, aguardiente is a more processed and flavored guaro.
Anoche dormí en el suelo, dormí en el suelo teniendo cama, por culpa de ese maldito, de ese maldito guaro de caña
In Central America, this is slang for "booze". Specifically, a brand name of booze called "Cacique" (which is awesome but I can't see to find around here anywhere!.
"Check out that guy.....mucho guaro!"