Slug

The slug at the front of the line was holding up everyone behind him.

He's always late for everything. He's such a slug when it comes to punctuality.

The ballistics expert analyzed the unique markings on the recovered slug to identify the type of weapon used in the crime.

He always takes forever to complete his tasks. He's such a slug.

She never wants to go for a walk or do any physical activity. She's such a slug.