adj.
 feeling or showing sorrow and regret for having done wrong.
n.
 a person who repents their sins. 
▸(in the Roman Catholic Church) a person who confesses their sins to a priest and submits to the penance that he imposes.
Derivative
  
    - penitence n.
- penitential adj.
- penitently adv.
 
  Etymology
  ME: from OFr., from L. paenitent-, paenitere ‘repent’.