to leave: to let go of someone or something, whether by simply walking away or by abandoning what one was bound to hold onto
At its core this word means to release one's hold and move away from a person, place, or thing. The same act can be morally neutral or morally loaded depending on what is left and whether a bond was broken. A man leaves his father and mother to marry; a fugitive drops the coat in his captor's hand; a farmer leaves the edge of his field for the poor. None of that carries blame.
The weight comes when what is left is something a person was obligated to keep. To leave a covenant partner, a parent, or God is not a neutral departure but a betrayal, and most of the heavy uses in the Bible are exactly this: Israel forsaking the LORD, or the cry that God has forsaken his people. The word does not change meaning; the gravity comes from the relationship being broken.
A third group sits between the two: to leave something behind for someone else to have, or to leave off an attitude or activity. Here the focus is on what is deliberately let go or set aside rather than on who is wronged. Across all of these the single thread is the loosening of a grip and a moving away from what was held.