soiling

1. To make dirty.
2. To become dirty or soiled.

   Light colours soil sooner than dark ones.

3. To stain or mar, as with infamy or disgrace; to tarnish; to sully.
4. To dirty one's clothing by accidentally defecating while clothed.
5. To make invalid, to ruin.
6. To enrich with soil or muck; to manure.

1. To feed, as cattle or horses, in the barn or an enclosure, with fresh grass or green food cut for them, instead of sending them out to pasture; hence (such food having the effect of purging them), to purge by feeding on green food.

   to soil a horse

noun

An act of making dirty.