ponderous

adjective6

1. •
   Heavy, massive, weighty.

   • [H]e saw, at the end of a shallow embrasure, a ponderous door of dark wood, braced with iron. — 1879
2. •
   Dull, boring, tedious; long-winded in expression.

   • Over supper the minister did unbend a little into one or two ponderous jokes. — 1863
3. •
   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. — 1852
4. •
   (figurative) Serious, onerous, oppressive.

   • In its court-yard—worthy of the Castle of Otranto in its ponderous gloom—is a massive staircase. — 1845
5. •
   (rare) 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. — 1660
6. •
   (no longer used) Dense.