Funnest vs. Most Fun
Adjectives have comparative and superlative forms that help us to compare different things. Comparative adjectives (bigger, taller) are used to compare two different things, while superlative adjectives (biggest, tallest) are used to compare more than two things. We typically form superlative adjectives by adding –est to the end. When an adjective is long, however, we add "most" in front of the word-most intellectual.
Traditionally, though, the word fun has not followed this pattern. The comparative form that is most accepted is more fun and the superlative form that is most accepted is most fun. Let's take a closer look at why.
Fun originally functioned as a noun and not as an adjective. While this has changed over time, it has affected the way in which we form the superlative form of fun. Nouns don't have a superlative form, so when comparing states of "fun," a noun phrase was created using "more" or "most."
Examples of fun used as a noun in a noun phrase:
1. We had the most fun on the water slide.
2. The most fun that the class had on the field trip was on the bus!
So, as fun has been used as an adjective, "most fun" was the acceptable superlative form:
1. The most fun ride was the water slide.
2. The most fun part of the field trip was traveling on the bus together!
Yet, there isn't anything grammatically incorrect about funnest. If we follow the technical rules, we should form the superlative form of fun (a short adjective) by making the word funnest.
1. The funnest ride was the water slide.
2. The funnest part of the field trip was traveling on the bus together!
Before you use funnest, though, you should be aware that the accepted form is still most fun. Some grammarians do not recognize funnest as a word, so in your formal writing it is still safest to use most fun.
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