Minor quibbling for the sake of ~~post engagement~~ clarity: The term "brainwash" is a literal translation of a term coined by Mao, itself a pun on a ritualistic "heartwashing" that was customary to spiritually "clean" yourself (before? after?) entering a temple. Mao was using it as basically a jocular way to refer to political reeducation. The literal translation itself was first produced by some niche orientalist author who was making theories about chicom mind control powers. It was then adopted by the establishment after those soldiers in the Korean War were, in fact, rehabilitated by China* and renounced the war, confessed to using chemical and biological weapons (which never happened according to the notoriously honest US State Department), and in some cases even fully refusing to be brought back to America, instead choosing to live in the PRC or DPRK.

Another "fun" one is "Ostalgie," a German portmanteau of "Ost" (east) and "Nostalgie" (nostalgia), which is the way that German popular culture characterizes the feelings of the former East Germans who preferred East Germany. It's another instance of pathologizing popular sentiments by treating them as some bizarre and peculiar psychological phenomenon rather than accepting that people have reason to think what they think.

*I think it was mostly by China, since China had a pretty dominant role late in the war, but that's not to say there was no Korean involvement or that every case with every supposedly-brainwashed prisoner was the same.