What is a root word?

A root word is defined as the base part of a word to which affixes (prefixes and suffixes) can be added. This core element carries the primary meaning of the word and serves as the foundation for forming various related words. For instance, in the word "unhappiness," "happy" is the root word, and the prefix "un-" and the suffix "-ness" modify its meaning. Recognizing root words is essential for understanding and constructing a wide range of vocabulary, as various prefixes and suffixes can alter or enhance the meaning derived from that root.

In contrast, the other options do not accurately describe a root word. A word that has no meaning does not contribute to vocabulary understanding. A suffix that describes a state refers specifically to certain endings that indicate a condition or quality but does not define what a root word is. Similarly, a synonym for a prefix does not pertain to the concept of root words and suggests confusion between different morphemes that compose words.