loyal
adjective
uk/lɔɪəl/ us COMMERCE, MARKETING
a loyal customer always buys the same product, uses the same store, etc.:
Supermarkets should reward their most loyal customers.
loyal to sb/sth Our customers remain loyal to the brand.
HR
a loyal employee works for the same company for many years:
loyal to sb/sth Training programmes encourage workers to remain loyal to their employers.