God-fearing: holding God in reverent awe, so that one lives faithfully and obediently
This is the dominant use of the word, and it names a settled character, not a passing emotion. To be God-fearing is to take God seriously enough that it shapes how a person lives: it goes hand in hand with turning from evil, keeping the commandments, dealing honestly, and trusting God. Job is introduced this way, and Abraham is declared to be this at the moment he proves willing to obey.
A standing phrase grew up around the word: the fearers of the LORD, a way of naming God's faithful people as a group. The Psalms return to it again and again, promising that those who fear the LORD are watched over, provided for, and kept close to him.
The word can also describe reverence aimed at a person rather than God, as when a court official speaks of fearing the king he serves. The idea is the same in either case: a deep respect for someone with rightful authority that governs how one behaves toward them.
This reverent fear is not the opposite of love or trust but their companion. The one who fears God is precisely the one urged to trust him and lean on him, which is why the Bible can hold up fearing God as the path to a good and secure life rather than a fearful one.