dyed-in-the-wool

Permanent and or firmly established, such as in one's opinions or beliefs. Good luck getting him to listen to your political views—he's a dyed-in-the-wool liberal.

[of someone] permanent or extreme. My uncle was a dyed-in-the-wool farmer. He wouldn't change for anything. Sally is a dyed-in-the-wool socialist.

COMMON You use dyed-in-the-wool to describe a supporter of a particular set of beliefs or a member of a particular group, meaning that their beliefs or feelings are very strong and will never change. I'm a dyed-in-the-wool Labour man so he'll not get my vote. Mr Purves has made Hong Kong his home for the past 38 years but he remains a dyed-in-the-wool Scotsman. Michael is a dyed-in-the-wool traditionalist. Note: In medieval times, wool was often dyed before it was spun and woven. This meant that colour was more evenly distributed in the wool, and lasted longer.

Thoroughgoing, complete. The term, which dates from at least the sixteenth century, alludes to cloth made from wool that was dyed while raw (before it was spun) instead of being dyed piece by piece. The color therefore was “true” throughout, and this concept was transferred to other kinds of genuineness. “In half an hour he can come out an original democrat, dyed in the wool,” said Daniel Webster in a speech (Feb. 10, 1830). It has been a cliché since the early 1900s.