Definition of perfectional in US English:

perfectional

adjective

rare
  • Perfect; of, relating to, or characterized by perfection.

Origin

Late 15th century; earliest use found in Trevisa's Bartholomeus De Proprietatibus Rerum. From post-classical Latin perfectionalis concerned with perfection from classical Latin perfectiōn-, perfectiō + -ālis. Compare Middle French perfectionnal relating to perfection.