Hold on to your hats, word snobs: you won’t be invited to the funnest parties if you keep correcting people on their use of “funner” and “funnest.” These words are acceptable forms of the adjective “fun” and you need to step off your high horse if you want to be funner to be around.
From Merriam-Webster’s recent newsletter:
Q. I have your 1991 dictionary and it shows that funner and funnest are listed as adjectives. Friends are arguing with me, saying funner is not a word, and there seems to be no definite answer that I can find while searching online. What’s the real story?
A. The superlatives funner and funnest are indeed both words, as your dictionary asserts. In the entry in that book, the words are preceded by the label sometimes to show that they are somewhat uncommon forms. Both words are found in casual speech, and are even occasionally used by writers in such publications as The Washington Post, The New York Review of Books, and the Boston Globe.
The reason for the lack of universal acceptance of funner and funnest has to do with the history of the word fun. Formerly only a noun, fun existed 100 years before the adjective sense developed. Noun uses like “have fun” and “do something for fun” were considered proper, while uses like “a fun game” and “it’s fun to do” were not used. While this changed over time, some people still do not consider fun an adjective, saying that it’s only being used attributively when it’s before a noun, as in “a fun game.” (Nouns are often used attributively before other nouns, such as school in school bus.) The fact that one thing can be described as “more fun” than another, though, is persuasive evidence for the adjective fun, and justification for the development of funner and funnest. Most writers and speakers avoid the superlatives because they sound a little odd because they are encountered more rarely. But the forms are nonetheless real and not slang.