Which suffix is a derivational suffix that changes the word class to form an adjective in many English words?

• A. -ful
• B. -ed
• C. -s
• D. -est

Answer: (A)

A suffix that turns a noun into an adjective by describing having that quality is -ful. When you add -ful to a noun, you describe something as being full of that noun’s quality. Examples include careful (full of care), joyful (full of joy), and beautiful (full of beauty). This suffix is productive in forming adjectives from many nouns, giving a clear, consistent way to describe something by the quality it possesses.

Other endings don’t fit this same function. -ed marks tense or forms participles, though some participles can serve as adjectives, the primary role is not to derive adjectives across a wide range of words. -s is a plural or third-person verb ending, not a derivational suffix for adjectives. -est signals the superlative form and is an inflectional ending, not a derivational one. Because -ful consistently and broadly creates adjectives from nouns, it’s the best choice.