When good is used as an attribute in a sentence, it means "good, happy". When used as a predicative in a sentence, good means making good use of (something), being good at handling (something) and being kind to (someone), followed by for can mean "beneficial and appropriate", followed by to can mean "right? Friendly, followed by at can mean "proficient". When good is used as a predicative, it can be followed by an infinitive.
3.good is often used as a courtesy or honorific, and sometimes as an irony, which means "contempt and ridicule".
4.good and adjectives are often used to emphasize mood in American spoken language, which means "very" and is equivalent to very.