Sherpa originally meant the tribe in Nepal whose social custom was to provide humane and courageous mountain guides to outsiders. This tribe didn't use last names, so they were all referred to as Sherpas. To the Sherpa, all Himalayan peaks are sacred, so every tour holds ethical and religious meaning. Westerners picked up on this and use Sherpa to mean an assistant who knows more than the boss.

An experienced guide helping others on a mountain climbing expadition.

A sober guide/leader who escorts the stoners into public situations

To fail a test so badly that if the test were re-curved using only the scores of the people who failed, you still would have failed.

one (usually of higher skill) who helps noobs beat a game or specifically a hard part of a certain level in exchange for an achievement or kills in which to level