English words deriving from acronyms dating from before WWII are uncommon and those dating from before WWI are practically nonexistent. “Okay” is about the only common one. Any claim that a word that wasn’t coined in the 20th century is an acronym is almost certainly false. Etymology Online just posted an indignant article about this, inspired by the “tag” urban legend that has popped up recently, in which he uses, quite appropriately IMHO, words like “appalling idiocy”, “bilge”, “dopes” and “intellectual vandalism”. He does list three more old-ish words that might be acronyms, but two date from only shortly before WWI and the other is probably not an acronym.