The word slalom was first used in a 1921 edition of the magazine for the Ski Club of Great Britain. It was borrowed directly from Norwegian slalam, which referred to downhill skiing races but more literally meant "sloping track". It's composed of the words sla, meaning "side of a hill", and lam, meaning "track". I can't find exactly where those terms come from, but some etymologists speculate that lam may be related to another Norwegian word meaning "row of houses". Ultimately, these probably trace to Old Norse, Proto-Germanic, and finally Proto-Indo-European. Usage of slalom peaked in the 1980s and '90s, and has been decreasing since, although Google searches for it obviously spike during every Winter Olympics. The verb form was first attested in 1973, and both slalomer and slalomist are correct names for "one who slaloms".
Adam Aleksic, a rising sophomore studying linguistics and government at Harvard University, has been described as the internet's sixth most famous etymologist. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.