Prefix and Suffix

Prefix
A prefix is a group of letters placed before the root of a word. For example, the word "unhappy" consists of the prefix "un-" [which means "not"] combined with the root (stem) word "happy"; the word "unhappy" means "not happy."

Suffix
A suffix is a group of letters placed after the root of a word. For example, the word flavorless consists of the root word "flavor" combined with the suffix "-less" [which means "without"]; the word "flavorless" means "having no flavor."