When describing something that does not fit, there are a variety of synonyms to choose from. For example, the word "incompatible" can be used to describe objects or ideas that are not able to work together, while "ill-suited" refers to something that is not appropriate for a particular situation or purpose. Another option is "misfit", which describes an object or person that is not the right shape or size for its intended use. Other synonyms for "not fitting" include "mismatched", "unfitting", "unsuitable", "incongruous" and "unbecoming". These words can be used to add variety and nuance to a piece of writing, allowing for more precise communication.