1. the act or process of making something foul, dirty, or polluted
2. something that fouls or pollutes; filth or contamination

Examples

• The befoulment of the river by industrial waste threatened the local ecosystem.
• Efforts to prevent befoulment of the water supply included stricter regulations on dumping.
• The befoulment of the sacred site was considered a serious offense.
• Chemical befoulment of the soil made farming impossible in that region.
• The city launched a campaign to reduce air befoulment from vehicle emissions.
• Ancient texts warned against the befoulment of temples and holy places.