stalwart
n.n. a person who is very loyal and hard-working. You use this to describe someone who supports a team, organization, or cause for a long time.
n. a person who is loyal, reliable, and devoted to a cause or organization. Often used to describe a long-standing member of a group who provides consistent support.
He has been a stalwart of the local football club for thirty years.
The team's success this season was largely due to the efforts of its stalwart defenders who never gave up.
While many of the original founders have moved on, the organization remains a stalwart of the community, providing essential services that have remained unchanged for decades.
Borrowed from Scots stalwart under the influence of Walter Scott, displacing earlier stalworth, wherewith it forms a doublet. From Middle English stal-worth (“physically strong, hardy, robust; brave, courageous”), from Old English stǣlwierþe (“able to stand in good stead, serviceable”), probably from staþol (“establishment; foundation”) (ultimately from Proto-Indo-European steh₂- (“to stand (up)”)) or stǣl (“place; condition, stead”) + -wierþe (“able to, capable of”) (probably ultimately from Proto-Indo-European wert- (“to rotate, turn”)).