“Information security” is too broad as it covers more than technological systems—sensitive information often exists on paper, for example.
A close plain English name would probably be something like “information systems security” and I have heard some people use that, but it’s kind of a mouthful.
I guess I wonder why people get so upset and offended by the word cyber. Sure it’s a made up word, but all words are made up. IMO a lot of the resistance to using it comes down to weird cultural signaling like “I’m too smart or informed to use this dumb word.” It’s just a word, and even people who complain about it know what it means.