Direct comparison
Adjective vs adverb
Adjectives modify nouns and pronouns; adverbs modify verbs, adjectives, other adverbs and sometimes whole clauses — the difference is what each word describes, not how it looks.
The step most authors miss
Doing CRediT right? Don’t stop at the statement.
A CRediT statement credits you inside one paper. The recognition CRediT was built for happens when those roles are tied to you, persistently. Sign in with your ORCID — free — and claim your CRediT contributions on casrai.org, the home of the standard. They become a verified, portable part of your identity, not a line that disappears into one PDF.
Free: claim your contributions, then export a journal-ready CRediT statement, schema.org structured data, JATS XML, CSV or BibTeX — and preview your public profile. A membership publishes that profile publicly and verifies the journals you serve.
Side-by-side comparison
| Dimension | Adjective | Adverb |
|---|---|---|
| What it modifies | Nouns and pronouns only. | Verbs, adjectives, other adverbs and whole clauses. |
| Core question answered | What kind? Which one? How many? Whose? | How? When? Where? To what degree? How often? |
| Typical position | Before the noun (attributive) or after a linking verb (predicative). | Flexible — before or after verb, before adjective/adverb, at sentence start or end. |
| Typical example | She gave a clear explanation. | She explained it clearly. |
| After linking verbs (be, seem, feel, look) | Use adjective: she feels nervous (describes she, not feels). | Do not use adverb: "she feels nervously" is incorrect for this meaning. |
| The -ly rule | Some adjectives end in -ly: friendly, lovely, timely, costly. | Many adverbs end in -ly (quickly, carefully) but not all (fast, well, hard). |
| Comparative and superlative | Adds -er/-est or more/most: clear → clearer → clearest. | Usually adds more/most: clearly → more clearly → most clearly. |
| Common error | Using adjective after action verb: "she writes clear" (should be clearly). | Using adverb after linking verb: "the soup smells badly" (should be bad). |
| "Well" vs "good" | Good is the adjective: "she is a good writer"; "she feels good" (health). | Well is the adverb: "she writes well"; also adjective meaning healthy: "she is well". |
| Flat adverbs (no -ly) | Hard, fast, late, early, high can all be adjectives: a hard question. | Hard, fast, late, early, high are also adverbs: she works hard; he arrived late. |
The linking verb test
The most common source of adjective/adverb confusion is the verb after a linking verb. Linking verbs — be, seem, appear, become, feel, look, smell, taste, sound, remain, grow — connect the subject to a description of the subject. That description must be an adjective, not an adverb, because it describes the subject (a noun) not the verb. "She looks nervous" uses the adjective nervous (describing her appearance); "she looks nervously" would mean her act of looking is nervous, which is a different, unusual claim. The test: replace the verb with is or seems. If the result still makes sense, use an adjective. "The soup smells bad" → "the soup is bad" works, so bad (adjective) is correct, not badly.
Flat adverbs and the good/well distinction
Several adverbs look identical to their adjective counterparts because they take no -ly suffix — these are called flat adverbs. Examples include fast, hard, late, early, high, long, straight and direct. "She works hard" and "it was a hard question" are both correct; hard performs different roles in each. Adding -ly creates a different word with a different or narrower meaning: hardly means scarcely, not in a hard manner; lately means recently, not at a late hour. The good/well pair is a special case: good is always an adjective (a good result, she is good at writing); well is the adverb form (she writes well) and also an adjective meaning healthy (she is well). "She did good" is non-standard in formal British and American English; "she did well" is correct.
Comparative and superlative forms
Adjectives and adverbs both form comparatives and superlatives, but the patterns differ. Short adjectives add -er and -est: clear, clearer, clearest. One-syllable and some two-syllable adjectives follow this pattern. Longer adjectives use more and most: more significant, most significant. Most adverbs ending in -ly use more and most: quickly → more quickly → most quickly. Flat adverbs again behave like adjectives: fast → faster → fastest; hard → harder → hardest. Irregular forms shared by both classes include good/well → better → best and bad/badly → worse → worst. Mixing the patterns (more quicker, more clear when clearer is standard) is a common error in non-native and informal speech.
Key facts
At a glance
- Adjective modifies: nouns and pronouns
- Adverb modifies: verbs, adjectives, adverbs and clauses
- Linking verb rule: use adjective after be, seem, feel, look, smell, taste (describes subject)
- The -ly rule: many adverbs end in -ly but not all; some adjectives also end in -ly
- Flat adverbs: fast, hard, late, early — same form as adjective, no -ly needed
- Good vs well: good is always an adjective; well is the adverb (and an adjective meaning healthy)
- Comparatives: short adjectives use -er/-est; most adverbs and long adjectives use more/most
Common misconceptions
What people often get wrong
Often heard: Any word ending in -ly is an adverb.
Actually: Many adjectives also end in -ly: friendly, lovely, timely, costly, lonely, silly. The -ly ending is a useful clue but not a reliable rule. Check what the word modifies: adjectives modify nouns; adverbs modify verbs, adjectives or other adverbs.
Often heard: Use an adverb after any verb.
Actually: After linking verbs (be, seem, feel, look, taste, smell, sound, become), use an adjective to describe the subject, not an adverb to describe the verb. "She felt bad" (adjective, describing her state) is correct; "she felt badly" means her sense of touch was poor — a distinct meaning.
Often heard: "Good" can be used as an adverb in formal writing.
Actually: Good is an adjective in standard formal English. The adverb is well: "she performed well", not "she performed good". While "she did good" is common in informal American speech, it is non-standard in formal British or academic writing.
Common questions
FAQ
What is the difference between an adjective and an adverb?+
An adjective modifies a noun or pronoun: it answers what kind, which one or how many. An adverb modifies a verb, adjective, another adverb or a whole clause: it answers how, when, where, how often or to what degree. The key test is what the word modifies — not how it looks or whether it ends in -ly.
How do I know whether to use "bad" or "badly"?+
Bad is an adjective; badly is an adverb. After a linking verb such as feel, seem, look or smell, use the adjective bad: "she feels bad" (she is unwell or sorry). "She feels badly" means her sense of touch is impaired — a different and unusual claim. For action verbs, use badly: "the project was managed badly".
Is "fast" an adjective or an adverb?+
Fast can be both. As an adjective it modifies a noun: "a fast car". As a flat adverb (one with no -ly form) it modifies a verb: "she drives fast". There is no separate adverb fastly. Similarly, hard, late, early, high and straight serve as both adjective and adverb, with -ly versions (hardly, lately) carrying different meanings.
Going deeper
