loy·al 
(loiəl)
(loiəl)adj.
1. Steadfast in allegiance to one's homeland, government, or sovereign.
2. Faithful to a person, ideal, custom, cause, or duty. See Synonyms at faithful.
3. Of, relating to, or marked by loyalty: thanked the voters for their loyal support.
[French, from Old French leial, loial, from Latin lēgālis, legal, from lēx, lēg-, law; see leg- in the Appendix of Indo-European roots.]
loyal·ly adv.