Green’s Dictionary of Slang

McJob n.

[brandname McDonald’s+SE job, popularized by Douglas Coupland in his book Generation X (1991). The use of McDonald’s refers both to the type of job, which epitomizes those available in the fast-food chain, and to what critics see as the disposable, tasteless, non-nutritional quality of the food the chain sells]

[1980s+] (orig. US) a pointless, usu. menial job with no prospects or job satisfaction.