steadfast
adj.adj. staying loyal and firm in your beliefs or actions, even when things get difficult. You use this to describe someone who does not change their mind or give up.
adj. firm and unwavering in purpose, loyalty, or resolve. Often used to describe personal character or commitment in the face of adversity.
She remained a steadfast friend during my hardest years.
Despite the economic downturn, the company remained steadfast in its commitment to environmental sustainability.
The leader's steadfast refusal to compromise on core principles eventually earned the respect of even her most vocal political opponents.
From Middle English stedefast, from Old English stedefæst, from Proto-Germanic *stadifastuz, equivalent to stead (“place; spot; position”) + fast (“firm; fixed”). Cognate with Middle Dutch stedevast (“steadfast”), Icelandic staðfestur (“steadfast”), Danish stedfast (“firmly attached, secured”), Danish stadfæste (“to confirm; ratify”), Norwegian Bokmål stadfeste (“confirm, ratify; establish”), Swedish stadfästa (“to confirm; establish”).
Typically used attributively before a noun or predicatively after a linking verb like 'remain' or 'stay'.