1. Undesirable state of the natural environment being contaminated with harmful substances as a consequence of human activities.[Wordnet]
2. The state of being polluted.[Wordnet]
3. The act of contaminating or polluting; including (either intentionally or accidentally) unwanted substances or factors.[Wordnet]
4. The act of polluting, or the state of being polluted (in any sense of the verb); defilement; uncleanness; impurity.[Websters]
5. The emission of semen, or sperm, at other times than in sexual intercourse.[Websters].