Adjective-Forming Suffixes

Level B1 · Adjectives & Adverbs

English often turns nouns and verbs into adjectives by adding a suffix — a word ending like -ful, -less, -able, -ive, -ous, or -y. Recognizing these suffixes helps you guess the meaning and part of speech of unfamiliar words: care (noun) becomes careful (having care) or careless (without care) — the suffix tells you it's now an adjective, and often signals whether the meaning is positive/full of something or negative/lacking something.

Common adjective-forming suffixes and their meanings:

• -ful = full of, having: careful (full of care), helpful (giving help), beautiful (full of beauty). -less = without, lacking: careless (without care), hopeless (without hope), homeless (without a home) — -ful and -less are often opposite pairs on the same noun: careful/careless, harmful/harmless.
• -able / -ible = capable of being [verb]-ed, and it attaches to a verb: read → readable (able to be read), wash → washable, afford → affordable, break → breakable. Beware of lookalikes: comfortable and responsible end the same way but are not built by this rule — comfortable does not mean 'able to be comforted' — so learn those two as ordinary vocabulary.
• -ous / -ious = having the quality of, full of: dangerous (full of danger), famous (having fame), curious (full of curiosity). -ive = having a tendency to, related to: active (tending to act), creative (having creativity), effective (producing an effect).
• -y = characterized by, having a lot of (often with weather, texture, or small nouns): rainy (having a lot of rain), sunny (full of sun), noisy (full of noise). -al / -ical = relating to: national (relating to a nation), musical (relating to music), historical (relating to history).

The most common mistake is confusing -ful and -less, which look similar but mean opposite things — a careful driver (full of care, safe) is the opposite of a careless driver (without care, unsafe); mixing them up completely reverses the meaning. A second mistake is guessing a suffix incorrectly for a specific word — not every noun accepts every suffix (hope becomes hopeful/hopeless, but 'hopeive' or 'hopey' don't exist); each word's correct suffix has to be learned, even though the general meanings of the suffixes are a useful guide.

Look at the ending of an unfamiliar word: -ful or -ous often signal 'having/full of' a positive or neutral quality; -less signals 'without/lacking' something; -able/-ible signals a capability or possibility; -y often describes weather, texture, or a quality made of many small parts. Use the base noun or verb the suffix is attached to as a clue to the adjective's core meaning.

Practice

Adjective-Forming Suffixes: Choose the Right Form · Mixed Practice