jerkwater (adj.)

also jerk-water, "petty, inferior, insignificant," 1890, earlier in reference to certain railroad trains and lines (1878); in both cases the notion is of a steam locomotive crew having to take on boiler water from a trough or a creek because there was no water tank; see jerk (v.1) + water (n.1). This led to an adjectival use of jerk as "inferior, insignificant;" hence also jerkwater town (1893).