Shamus, n. [Yiddish]:
A shamus is a guy who takes care of handyman tasks around the
temple, and makes sure everything is in working order.
A shamus is at the bottom of the pecking order of synagog
functionaries, and there's a joke about that:
A rabbi, to show his humility before God, cries out in the
middle of a service, Oh, Lord, I am nobody! The cantor, not to be
bested, also cries out, Oh, Lord, I am nobody!
The shamus, deeply moved, follows suit and cries, Oh, Lord, I
am nobody! The rabbi turns to the cantor and says, Look who thinks
-- Arthur Naiman, Every Goy's Guide to Yiddish