Nonnatural is a word that describes something that is not found in the natural world, or something that is not considered natural. There are many synonyms for nonnatural that can be used to describe something that is unnatural or artificial. For example, synthetic, man-made, artificial, manufactured, fabricated and unnatural are all synonyms for nonnatural. Each of these words can be used to describe something that is not natural, whether it is a product created in a laboratory, or an idea that is not in line with natural or common-sense beliefs. Whatever the context, nonnatural can be replaced with a variety of synonyms to describe something that is not considered to be natural or organic in origin.