When we talk about something that is unnatural in form, it means that it does not conform to the natural shape or design of things. There are several synonyms for this term that can be used to describe such objects or items. These synonyms include aberrant, anomalous, atypical, irregular, unorthodox, and eccentric. These words can be used to describe anything that is unusual or deviates from the norm. For instance, an unusual rock formation in a landscape can be described as anomalous or aberrant. Similarly, a piece of art that doesn't fit the conventional design or style can be labeled as unorthodox or eccentric. These synonyms allow us to convey the idea of uniqueness or distinctiveness in a better way.