noun

• The act or process of contaminating
• Something which contaminates.
• (linguistics) A process whereby words with related meanings come to have similar sounds.
• (linguistics, etymology) The influence of one form (often from a foreign language) on the historical development of another form to which it may be related in meaning.
• The process of making a material or surface unclean or unsuited for its intended purpose, usually by the addition or attachment of undesirable foreign substances.