1.NounThe exercise of authority or power in a burdensome, cruel, or unjust manner.
2.NounThe act of oppressing, or the state of being oppressed.
"Extreme freedom is followed by extreme oppression, said Plato."
3.NounA feeling of being oppressed. Special usage may include a sense of heaviness or obstruction in the body or mind; depression; dullness; lassitude.
"Our oppression was lifted by the reappearance of the sun."