Well and Good : English Glossary

In both casual speech and formal writing, we frequently have to choose between the adjective good and the adverb well. With most verbs, there is no contest: when modifying a verb, use the adverb.

He swims well.

He knows only too well who the murderer is.

However, when using a linking verb or a verb that has to do with the five human senses, you want to use the adjective instead.

How are you? I'm feeling good, thank you.

After a bath, the baby smells so good.

Even after my careful paint job, this room doesn't look good. Many careful writers, however, will use well after linking verbs relating to health, and this is perfectly all right. In fact, to say that you are good or that you feel good usually implies not only that you're OK physically but also that your spirits are high.

How are you?

I am well, thank you.

Bad versus Badly :

When your cat died (assuming you loved your cat), did you feel bad or badly? Applying the same rule that applies to good versus well, use the adjective form after verbs that have to do with human feelings.

You felt bad.

If you said you felt badly, it would mean that something was wrong with your faculties for feeling.