Meaning of ponderous

(adj) slow and laborious because of weight; "the heavy tread of tired troops"; "moved with a lumbering sag-bellied trot"; "ponderous prehistoric beasts"; "a ponderous yawn"

having great mass and weight and unwieldiness; "a ponderous stone"; "a ponderous burden"; "ponderous weapons"

labored and dull; "a ponderous speech"