allegiant
/əˈliːdʒ(ə)nt/adjective
That owes or gives allegiance (to someone or something); loyal, faithful.
noun
A person who owes or gives allegiance; a loyal follower or adherent (of someone or something).
Origin
Mid 16th century; earliest use found in John Heywood (c1496–c1578), playwright and epigrammatist. From allegi- + -ant, by analogy with other adjectives and nouns in -ant corresponding to nouns in -ance.