dyed-in-the-wool supporter

Translations
убежденный сторонник
He is a dyed-in-the-wool supporter of the team, attending every game.
Он является убежденным сторонником команды, посещая каждую игру.
Definitions
A dyed-in-the-wool supporter is someone who is a staunch and unwavering advocate for a particular cause, belief, or organization, often showing deep loyalty and commitment that is unlikely to change.
Words
dyed

adjective
убежденный
in

preposition
в
the

article or possessive pronoun
определенный артикль
wool

noun
шерсть
supporter

noun
сторонник