“Fee-for-service.” Your reader knows that a fee is an amount of money he has to pay for a service, so when he encounters the adjectival phrase “for service,” it sounds redundant. He wonders, “As opposed to what? A fee for something other than service? A fee that entitles me to no service?” A service with no fee? A service offered in barter?Similarly:
“Sugar diabetes.” Are there types of diabetes that have nothing to do with blood sugar?
“Core fundamentals.” What other kinds of fundamentals are there? Extraneous fundamentals? Tangential fundamentals?
A “Freshwater Rinse” button on a washing machine. As opposed to what? A salt-water rinse?The Takeaway: Remember, your reader can’t read your mind. If you combine a familiar noun with a redundant-sounding modifier, tell your reader what you are talking about. If you don’t, he may become distracted. Anticipating and preventing his distraction is part of the job of writing.