"theater patron in the pit" (which originally had no floor or benches), c. 1600, from ground (n.) in an Elizabethan sense of "pit of a theater" + -ling. From the beginning emblematic of bad or unsophisticated taste. Old English grundling was a type of fish.
grounded
grounder
ground-hog
grounding
groundless
groundling
grounds
ground-swell
groundwater
groundwork
group