adjective

feeling or expressing remorse at the recognition that one has done wrong.

a contrite tone

remorseful,repentant,penitent,regretful,full of regret,sorry,apologetic,self-reproachful,rueful,sheepish,hangdog,ashamed,chastened,shamefaced,conscience-stricken,guilt-ridden,in sackcloth and ashes,compunctious