"Good" is an adjective that describes nouns; "well" is an adverb that describes verbs, adjectives, or other adverbs (and as an adjective means "in good health").
Adjective: of high quality, correct, pleasant, or beneficial. Always describes a NOUN or PRONOUN. "A good book" = a high-quality book. "The food is good" = the food is tasty/of good quality. "She is a good teacher" = she is a skilled teacher. Also follows state verbs (linking verbs): "I feel good" = I feel in a positive emotional/physical state (describes the state, not how I act).
That was a really good decision — taking the longer route avoided the worst of the traffic.
I feel good about the interview — I was well prepared and the questions were exactly what I expected.
She is a good listener — people always feel heard after talking with her.
Adverb: in a satisfactory, skilled, or correct manner. Describes VERBS ("she sings well"), ADJECTIVES ("well prepared"), or other ADVERBS. As an adjective: "He is not well" = he is not in good health. "Are you well?" = are you healthy? "Well" as an adjective ONLY means "in good health".
He speaks English extremely well for someone who only started studying it two years ago.
The presentation went well — the audience asked great questions and the CEO seemed impressed.
She has not been well since the operation — she needs more time to recover fully.
Common mistake
The most common error in the English-speaking world (not just among learners): "She did good" when it should be "She did well". "Do" is an action verb, so it needs an ADVERB ("well"), not an adjective ("good"). "She did good" is grammatically incorrect but so common that many native speakers use it in informal speech. The rule: after ACTION verbs (run, sing, do, play, work, speak) = WELL. After STATE verbs (feel, look, seem, taste, be, sound) = GOOD.
Trick to remember it
Key question: is the word modifying a NOUN or a VERB? NOUN = GOOD. VERB = WELL. Examples: "a good singer" (good modifies "singer", noun = GOOD). "She sings well" (well modifies "sings", verb = WELL). Important exception: state verbs (feel, look, seem, taste, smell, sound, be). These verbs link the subject to a description of itself, not an action. So: "I feel good" (good describes your STATE, not how you perform the act of feeling). "The soup smells good" (good describes the soup, not the act of smelling). All other verbs = WELL.
Quick rule
Good = adjective, describes nouns and follows state verbs (feel, look, seem, taste). Well = adverb, describes action verbs. As an adjective, well only means "in good health".
Did you know?
"I am doing good" vs "I am doing well" is one of the most famous grammar debates in modern English. "I am doing good" (meaning "I am fine") is so common in American English that many dictionaries already accept it as valid informal usage. Maximum irony: the formally correct version is "I am doing well", but "doing good" can also be interpreted as "I am doing good in the world" (good as a noun = moral good). So "I am doing good" technically means "I am benefiting humanity", not "I am in good health". Grammar is never boring.
Exercise 1 · Pick the right one
The team performed really _____ under pressure — they won the match despite being down two points at halftime.
Exercise 2 · Pick the right one
That is a _____ point — I had not considered that angle before.
Exercise 3 · Form the word
Good = adjective, describes nouns and follows state verbs (feel, look, seem, taste). Well = adverb, describes action verbs. As an adjective, well only means "in good health".
The most common error in the English-speaking world (not just among learners): "She did good" when it should be "She did well". "Do" is an action verb, so it needs an ADVERB ("well"), not an adjective ("good"). "She did good" is grammatically incorrect but so common that many native speakers use it in informal speech. The rule: after ACTION verbs (run, sing, do, play, work, speak) = WELL. After STATE verbs (feel, look, seem, taste, be, sound) = GOOD.
Key question: is the word modifying a NOUN or a VERB? NOUN = GOOD. VERB = WELL. Examples: "a good singer" (good modifies "singer", noun = GOOD). "She sings well" (well modifies "sings", verb = WELL). Important exception: state verbs (feel, look, seem, taste, smell, sound, be). These verbs link the subject to a description of itself, not an action. So: "I feel good" (good describes your STATE, not how you perform the act of feeling). "The soup smells good" (good describes the soup, not the act of smelling). All other verbs = WELL.
Bryan López
Founder of SpeakUP Academy