penitential
1. [ adjective ] of or relating to penitence or penance
Examples:

"the Day of Atonement is the great penitential day of the Hebrew calendar"

Related terms: repentance
2. [ adjective ] showing or constituting penance
Examples:

"penitential tears" "wrote a penitential letter apologizing for her hasty words"

Related terms: penitent
Similar spelling:   penitentially
  penitent
  penitentiary
  penitently
  penitence