A suffix is a letter or set of characters, such as '-ly' or '-ness,' that is appended to the end of a word to create a new word, usually of a different word class. The suffix '-ly', for example, is added to 'quick' to form 'quickly.'
-ed, -ing, -ly, and -s are the four most prevalent suffixes.
Suffixes are widely used to indicate a word's part of speech. When you add "ion" to the verb "act," you get "action," which is the noun form of the word. Suffixes also indicate whether words are multiple or singular, as well as their verb tense.
A suffix is a letter or a group of letters added to the end of a word to change its meaning or guarantee that it fits into a phrase properly. Suffixes (additions to the end of words) contrast with prefixes (additions to the beginning of words) (added to the front). Affixes include suffixes and prefixes.