Sludgy (adjective)

1. Thick, heavy, and viscous, as a liquid or semi-solid material.
2. Slow-moving and heavy.
3. Resembling or containing sludge.

Origin:

From "sludge" meaning "a thick, heavy, or viscous liquid or semi-solid material".

Examples:

1. The sludgy oil was hard to pump.
2. The sludgy mixture was difficult to stir.
3. It was a sludgy and slow-moving river.
4. The sludgy consistency of the mud made it hard to move.
5. The sludgy substance was a byproduct of the industrial process.