Loyal and committed to someone or something, or firmly determined and reliable.
From Middle French 'estaunch' and Old French 'estanche' meaning watertight or firm. Applied to people to mean reliable and steadfast, like a watertight structure.
A 'staunch' person is loyal like a watertight boat—water can't get in because the ship is solid, and similarly, nothing can make a staunch supporter abandon their cause!
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