What is an affix?

An affix is defined as an additional element that is added to the beginning or end of a word to modify its meaning or create a new word. This can include prefixes, which are added to the front of a word, and suffixes, which are added to the end. For example, the prefix "un-" can be added to the word "happy" to form "unhappy," indicating the opposite meaning.

The other options do not accurately capture the definition of an affix. Punctuation does not involve the modification of word meanings through the addition of elements. A word that describes an action refers to verbs rather than components that alter existing words. Lastly, a synonym for a root word refers to another word that has the same or similar meaning, which is unrelated to the concept of adding elements to modify or create words.