Usually what crashfrog described is someone who only has positions as a relation to others, and is described by their lack of alignment. This person would likely be called an Independent if they held strong, multidirectional views (like a Libertarian that loves the idea of universal Healthcare and UBI), and as such doesn't align with any mainstream party. If they hold relatively weak, multidirectional or otherwise views, they would be considered "moderate," though it's worth noting that the Democrat party is the moderate, liberal party, and as such the republican party and those between the democrats and Republicans are not moderates, but right-wing.

That's why it gets messy, the US only has right wing parties of varying degrees.