affirmant
/əˈfəːm(ə)nt/noun
A person who affirms (something); a person who makes a statement or declaration.
adjective
Chiefly Law and Logic. That affirms something. Now rare.
Origin
Mid 16th century. As noun from Anglo-Norman and Law French affermant, Law French affirmant, use as noun of present participle of affermer, affirmer. As adjective from classical Latin affirmant-, affirmāns, present participle of affirmāre. Compare -ant.