sorry
apologize
apology
regrettableness
apologetic
apologetically
sorriness
repine
afterthink
apologization
penitent
repentant
rue the day
regrettable
apologeticness
with respect
regretting
deprecatory
remorseful
remorsefulness
eat humble pie
apologeticism
own up
make a clean breast of
fess up
non-apology
beg someone's pardon
wear sackcloth and ashes
repent
eat one's words
regretfully
lamentably
could have, would have, should have
ochanee
look back
forgiving
unapologetic
condone
my apologies
regrettingly
excusatory
I beg your pardon
attrition
guilt
offcome
excuse
remorsefully
plea
guilt trip
self-reproach