The Catechism in Questions & Answers

651. What is meant by repentance and remorse?

Repentance signifies the recognition that one has acted wrongly, and incorporates remorse, as well as the earnest resolution to overcome mistakes and weaknesses.
Remorse is the feeling of suffering caused by wrongs committed in deed or omission. Sincere remorse also shows itself in the willingness to reconcile with one’s neighbour and make amends, as far as possible, for any damage that has been done.