Have you ever been chided for answering the question "How are you?" with "I'm good"? If so, here's some vindication.
It's such a simple little question: How are you? But I've heard from people who feel a twinge of trepidation or even full-blown frustration every time they have to decide whether to say they're good or they're well.
“I'm good” is what you're likely to hear in general conversation, but there are grammar nitpickers out there who will chide you if you say it. The wonderful news is that those nitpickers are wrong: it's perfectly acceptable to say, “I'm good,” and you shouldn't have to shamefully submit to teasing remarks such as the time-honored and leering, “How good are you?”
Say "I'm Good" with Confidence
The nitpickers will tell you that "well" is an adverb (and therefore modifies verbs) and that "good" is an adjective (and therefore modifies nouns), but the situation isn't that simple.
The key is to understand how linking verbs differ from action verbs. (Trust me, this is worth it so you can look people in the eye and say, “I'm good,” with absolute confidence.)
First, let's talk about action verbs. They're easy; they describe actions. Verbs such as "run," "jump," and "swim" are all action verbs. If you want to describe an action verb, you use an adverb like well. You could say: "He runs well"; "She jumps well"; "They swim well." "Well" is an adverb that relates to all those action verbs.
Linking verbs, on the other hand, are more complicated. Linking verbs aren't about actions as much as they are about connecting other words together. (1, 2) They're also sometimes called “copulative verbs.”
I think of the verb "to be" as the quintessential linking verb. The word "is" is a form of the verb to be, and if I say, "He is yellow," the main purpose of "is" is to link the word "he" with the word "yellow." Other linking verbs include "seem," "appear," "look," "become," and verbs that describe senses, such as "feel" and "smell." That isn't a comprehensive list of linking verbs—there are at least 60 in the English language (1)—but I hope that will give you an idea of how they work.
One complication is that some verbs—such as the sensing verbs—can be both linking verbs and action verbs. (2, 3) A trick that will help you figure out if you're dealing with a linking verb is to see if you can replace the verb with a form of to be; if so, then it's probably a linking verb. (1, 4) For example, you can deduce that "feel" is a linking verb in the sentence "He feels bad" because if you replace feels with the word "is," the sentence still makes sense: "He is bad." On the other hand, if you have a sentence such as "He feels badly," and you replace "feels" with "is," it doesn't make sense anymore: You get "He is badly." So in that case you know that "feel" is functioning as an action verb.