incumbent — as in: incumbent upon her to
It’s incumbent upon her to clean up the mess she created.
necessary (for someone) as a duty or responsibility
Much more rarely (and generally archaically) "incumbent" can also mean resting, leaning, or bent downward; e.g.:
- Two incumbent figures, gracefully leaning upon it.
- The incumbent geological formation...
- To move the incumbent load...
- The incumbent toe of a bird.