verb
molder
MOHL-der/ˈməʊldər/
To decay slowly.
The abandoned chest molders in the damp corner, its lower boards crumbling.

Etymology
Molder probably pictures decay as turning into loose earth or dust. On this analysis, its ending marks a repeated process, fitting the gradual crumbling of something left to decay.
More examples
- Fallen leaves molder beneath the trees all winter.
- The letters had moldered for decades in a leaky trunk.
- Her ambitious plans molder while she waits for funding.
Forms
molder · molders · moldered · moldering