to be good: to be sound, pleasing, or going well, and (in its causative form) to do good or do well
This is the verb behind one of the Bible's most basic value words. At its core it simply means that something is good, and the writers let context decide what kind of good is in view. A thing can be good in itself (sound, fine, beautiful), good to someone (pleasing, agreeable, welcome), or good for someone (their life is going well, they are prospering). The same verb covers all three, because in Hebrew thinking these are not separate ideas but one quality seen from different angles.
The first shade is the plainest: a thing simply is good. God looks at what he has made and sees that it is good (Genesis 1); a piece of land, a poem of love, or the LORD himself can all be called good in this way. The second shade is relational. Something seems good in a person's eyes, that is, it pleases them or wins their approval, and a closely related expression describes a heart that has turned merry, often with wine. The third shade looks at outcomes: it is well with a person, life goes well for them, they flourish.
The verb also has a causative form that shifts the meaning from being good to making good, that is, doing well or doing right. When God tells David or Jehu that they did well in what they set out to do, this is the form in use.
Because the word is so ordinary, the trap is to flatten it. English splits it into many renderings (be good, be pleasing, be merry, go well, do well), but in Hebrew it is one supple word for goodness in all its plainness.