ponderous

Heavy, massive, weighty.

[H]e saw, at the end of a shallow embrasure, a ponderous door of dark wood, braced with iron.

The great elephant, when the cage was being placed, would, at a signal from its keeper, place its ponderous head against one side of the cage and push.

Serious, onerous, oppressive.

It was Dryden's opinion . . . that the drama required an alternation of comick and tragick scenes; and that it is necessary to mitigate, by alleviations of merriment, the pressure of ponderous events, and the fatigue of toilsome passions.

In its court-yard—worthy of the Castle of Otranto in its ponderous gloom—is a massive staircase.

Clumsy, unwieldy, or slow, especially due to weight.

[T]he inmates of the coach, by numerous hard, painful joltings, and ponderous, dragging trundlings, are suddenly made sensible of some great change in the character of the road.

Slowly, through an increasing glow that lighted land and water alike, the leviathan of the deep made her ponderous progress to the hill-encircled harbor.

Dull, boring, tedious; long-winded in expression.

Over supper the minister did unbend a little into one or two ponderous jokes.

[A]s certainly as any one said anything in her presence that she had occasion to repeat, she changed the wording to six-syllabled mouthfuls, delivered with ponderous circumlocution.

Characterized by or associated with pondering.

Ponderous thoughts take hold of the heart; musing maketh the fire to burn, and steady sight hath the greatest influence upon us.

The acute and ponderous mind of Dr. Johnson was not always right in its decisions.