To get high. It seems (to me) that the word probably derives from the Spanish verb "chumar," which can refer to
intoxication by
everything from alcohol to hallucinogens, and which derives from "achuma," the mescaline-containing San Pedro cactus native to the high, dry areas of South America. Conjugation: chumo, chumas, chuma, chumamos, chumaís, chuman. "Estoy chumando duro" = "I'm
tripping hard."
A self-selected group of boys (including
Barack Obama) at Punahou School who loved basketball and
good times called themselves the Choom Gang. Choom is a verb, meaning “to smoke
marijuana.”