- the coldest day (i.e. the best example of a cold day, or the day that is colder than all the others)
- the craziest man
- the fluffiest cloud
In English, most superlatives can be formed by adding -EST to an existing adjective, like the examples above. (For adjectives that end in "-y", like "crazy", you often change the "y" to an "i" before you add the -EST on the end.)
Some adjectives have irregular superlative forms, which do not follow the rules, such as far ("farthest") and bad ("worst").
Other adjectives have no superlative form at all, and the superlative is made simply by adding the adverb "most" before the adjective. For instance, you do not say "funnest," or "interestingest". Instead, you say "most fun," and "most interesting." This way of making the superlative is used for almost all adjectives ending in "ing" (like "interesting", "fascinating", "disgusting" or "appealing".)