A person who believes in the doctrine of consubstantiation as an explanation of how communion works.
From 'consubstantiation' + '-ist' (adherent of a belief). The '-ist' suffix labels someone who holds or advocates for the consubstantiational view.
This word is basically the label for Lutheran theology on communion—different Protestant churches identified themselves partly by which long, Latin-based word they used to describe their beliefs about bread and wine.
Complete word intelligence in one call. Free tier — 50 lookups/day.