Person who works in a mindless/lowpaying/repetitive job (usually in retail). This person has barely enough mental capacity to perform his/her simple tasks with an acceptable success rate. He/she will almost never learn from the mistakes of their repetitive past and will never cease to astound you with their ability to look stupid.
Source: scumbag electronic stores in ny
"So...I see you hired another schenph?"
"Make the schenph to do it."
"LOL These new batch of schenphs are even dumber than the last"
"Sander is such a schenph, hes been workin here the longest, and gets paid the least"