to rebel: to defiantly refuse to obey a rightful authority, above all God himself.
This verb names open defiance against someone a person is bound to obey. It is not a quiet failure or an honest mistake; it is a deliberate refusal to listen and submit. The same word can describe a child who will not heed a parent or a people who will not heed a leader, but its center of gravity is the relationship between God and his people.
By far the most common picture is Israel defying the LORD. The verb is repeatedly paired with refusing to listen to his voice, and its usual object is his "mouth," a way of saying his spoken command. To rebel, then, is to hear a clear word from God and set oneself against it. The retellings of the wilderness years return to this charge again and again: the people rebelled at the sea, in the desert, and at the waters of Meribah, and a psalm and a sermon alike sum up a whole generation as stubborn and rebellious.
The word carries real heat. It is close to the language of treason against a king, now aimed at God, and it stands beside grieving his Spirit and provoking him to anger. When the people confess it, as in Lamentations, it is an admission of guilt, not a complaint. This is why it sits so naturally next to words for sin and transgression: rebellion is not one failing among many but the posture behind them, a will turned against the one it owes obedience to.