Origin
Gosu has cognates in Chinese and Japanese. In Chinese, 1993 gao shou (hangul: 고수, hanja: 高手, literally "high hand") is used for a person with skill, usually in martial arts or in baduk (the game of Go).[2] In the dialect of the Gyeongnam province, gosu also has the meaning of "leader".[3] The word is derived from the Chinese term 高手 gāoshǒu, and is similar to the Japanese word 上手 jōzu (literally "upper hand").

There are several English backronyms of the Korean word, mostly originating in the StarCraft community, including "Graduate of StarCraft University", "God Of StarCraft Universe" or "Guardian of StarCraft Universe".

Related terms
Though not as popular, there are also several other commonly used Korean words for describing gamers with various skill levels. Jungsu (hangul: 중수, hanja: 中手, literally "middle hand") stands for "a moderately good player", hasu (hangul: 하수, hanja: 下手, literally "low hand") for "a mediocre player" or "a person with no skill" and chobo (hangul: 초보, hanja: 初步, literally "first step") for "a novice player". "Hasu" and "chobo" are the same skill level, but "hasu" is disrespectful or derogatory, whereas "chobo" is not. The English equivalent to chobo would be newbie and hasu would be noob or lamer. A large European StarCraft, Warcraft III, DotA community, GosuGamers.net [1], is named after the term, as is online tournament gaming community GetGosu.com [2].

Synonyms
leet or 1337
über