General:
* Sluggish: This implies a lack of energy or enthusiasm.
* Leisurely: This implies a relaxed and unhurried pace.
* Gradual: This implies a slow and steady progress.
* Languid: This implies a lack of energy or vitality.
* Dilatory: This implies a tendency to delay or procrastinate.
Specific to speed:
* Crawling: This implies extremely slow movement.
* Dragging: This implies a slow and difficult movement.
* Meandering: This implies a slow and winding movement.
* Dawdling: This implies a slow and careless movement.
Specific to time:
* Prolonged: This implies something that lasts for a long time.
* Drawn-out: This implies something that is slow and tedious.
* Tedious: This implies something that is boring and slow.
The best word to use will depend on the specific meaning you are trying to convey.