slug·gish·ness noun (-es) Etymology: Middle English sluggusnes, from sluggus sluggish + -nes -ness : the quality or state of being sluggish: as a.: disinclination to activity : indolence < mental sluggishness > b.: slowness of movement < silt adding to the sluggishness of the creek > c.: economic stagnancy < the post-holiday sluggishness of department store sales >