1a spectator or reader of inferior taste, such as a member of a theater audience who traditionally stood in the pit below the stage:Dante is not for groundlings
[with reference to Shakespeare's Hamlet iii. ii. 11]
2a person on the ground as opposed to one in a spacecraft or aircraft. 3a fish that lives at the bottom of lakes and streams, especially a gudgeon or loach. 4a creeping or dwarf plant.