הטוב והמיטיב

What does it mean to describe God as "good"? In a philosophical light, to describe God as good is trivial it doesn't tell us anything about God. This is one of the major problems brought up in Ethical Philosophy and the Euthyphro Problem.

If it doesn't tell us anything about God, then why do we refer to God as good? Probably because it can tell us something about our relationship to God. God is the source of everything, good and evil.

...If we take the position that God's actions are just and good, then can we not infer something about the author of these actions, that His nature is just and good, or... Something that can be described as "just" and "good"? Maimonidies would respond that we can make the inference, but we haven't really learned anything new about the divine nature, just as we haven't learned anything new about fire's nature to burn when we observe that fire burns. What we want to know is the explanation why fire burns; we want to understand what it is about fire that, given the right conditions, it must burn. While we may be able to do this in the case of fire, we cannot explain God in that way.
Charles Manekin "On Maimonides" p.28

In other words, we want to know why God is good. Is good a term that we describe ourselves with and apply it towards God?

God's oneness implies not merely unity or simplicity but uniqueness. There is no relation between God and his creatures; hence He shares nothing in common with them...If that is the case, continues Maimonides, then

the terms "“knowledge","“power","“will", and "life",” as applied to Him, may He be exalted, and to all those possessing knowledge, power, will, and life, are purely equivocal, so that their meaning when they are predicated of Him is in no way like their meaning in other applications (1.56, p. 131).

It is not sufficient to say, for example, that God is infinitely wiser than we are. For that still implies that God and we share something in common called "“wisdom"” (although He has a lot more of it than we have!) So when we describe God as "wise",” we have to add something like the qualifying phrase, by "‘wise" we mean something entirely different from what we mean when we use "wise" with reference to us.
Manekin p.29

So in describing God as being good, we're relating to God the way we would relate to each other, but this is only because of our limited capability in comprehending God. In reality God's goodness is far beyond anything that we could imagine.