thickheaded; slow-witted; phlegmatic
Describes a person's mental dullness or temperamental slowness; often carries a negative or critical tone. Can refer to a lack of quick understanding or a stolid, unresponsive nature.
He is thickheaded and doesn't get jokes.
The public is frustrated by that politician's slow-witted responses.
slow-moving; sluggish
Refers to physical slowness or heaviness of movement, often implying a lack of agility or energy. Can describe people, animals, or even processes.
Frogs in winter are sluggish and easy to catch.
Seeing his slow movements, the coach decided to substitute him.