We tend to conceptualize the terms oppression, suppression, and repression to mean exactly the same thing in general conversation and while this is not true, they are nonetheless, interrelated.
To repress is to keep under control, to keep down or to suppress.
To suppress is to put an end to the activities of a person, body of persons, etc.
To oppress is to burden with cruel or unjust restraints, subject to a burdensome or harsh exercise of authority.
The aim of all three of these is to seek to control a person or group of people for some end that is not defined by the subject but, rather, by the object. Any time person (A) seeks to limit or control the actions or thoughts of person (B) is an expression of repression. Both suppression and oppression are means to achieve repression. At the core of this is the denial of person (B)’s agency by person (A), which is in turn a rejection of person (B)’s humanity. This is precisely how Paulo Friere defines oppression and what is wrong with it in the book Pedagogy of the Oppressed.
However, the situation is a bit more complex because not all acts that appear to fit the definition of repressive are by their very nature unjust. To seek to control the actions or the thoughts of a rapist, molester, or murderer, or an anti-Black racist Ku Klux Klan member with the aim of preventing harm to others is not necessarily unjust. The factors that may make such repression unjust are not the repression, but the manner in which the repression is carried out. For example, murdering members of a racist group merely for their affiliation and not because they have themselves done anything harmful. To do so is to become the oppressor and not to achieve real liberation for our people, as Paulo Friere argues can happen. Furthermore, this is by definition one of the conditions of genocide.
On the other hand, accountability circles and restorative justice practices which bring into focus a person’s behavior respecting their agency and humanity and working through what was wrong with a particular situation and working with them to grow so as not to recreate those same harms is a just form of seeking to help a person develop their thoughts and actions. As such, this overcomes the definition of oppression and is not exactly consistent with suppression because it is not an outside entity that shifts the behavior of person (A), but rather internally within person (B) because through a process of reconciliation their analysis has broadened and deepened, thus, becoming more humanizing.
Understanding these terms and what they mean is vital to developing our critical analysis of the conditions under which we live through deep personal and interpersonal examination. Furthermore, it permits us to engage with the complexity of social organization and what may on the surface appear to fit the definitions of oppression, suppression, or repression and to draw a clearly defined boundary between the just and the unjust practices, policies, procedures, and socialization processes of our world.