loyalest
loy-al-est
adjective
Having the greatest or most unwavering faithfulness and devotion to a person or cause.
"She was the loyalest friend I ever had."
Thesaurus
Synonyms: nationalistic, ultranationalistic, flag-waving, loyal, chauvinistic, jingoistic, superpatriotic, patriotic, true-blue, allegiant, liege, hardcore
Antonyms: disloyal, unpatriotic