Oppression is enforcement of unjust laws or practices. It invariably includes some form of denial of rights, and often persecution. Historically, oppression is characterized by harsh laws, severe punishments and efforts to destroy any opposition to the oppressor. Oppression is commonly based on religious, ideological, or some form of social grounds, like oppression of ethnic minorities.
In another context, the word 'oppression' may refer to a situation which is intolerable.