sluggish
Moving very slowly and without much energy or strength.
Sluggish means moving or working slowly, as if you're dragging through thick mud. When you wake up feeling sluggish on a Monday morning, your body feels heavy and slow, like it takes extra effort just to get out of bed. A sluggish computer takes forever to load a webpage, making you wait and wait while it processes information at a crawl.
Just like a slug inches along at a snail's pace (actually, slower than a snail's pace), something sluggish lacks energy and speed.
You might notice your bike feels sluggish when the tires need air, or a stream becomes sluggish during a dry summer when there's less water flowing through it. A sluggish economy means businesses aren't growing quickly. Even your thinking can be sluggish when you're tired or distracted.
The word describes slowness combined with a lack of energy or vigor, like something is weighed down or not working at full power. When a runner complains her legs feel sluggish during a race, she means they aren't responding with their usual strength and quickness.