lament
bemoan
deplore
bewail
compunction
self-reproach
remorse
fear
regret
too bad
regrettable
regrettingly
live to regret
regretlessness
guilt
shame
regretfully
ruesome
rue the day
apology
wear sackcloth and ashes
regretful
could have, would have, should have
whip the cat
regrettableness
desire
oblivion
obliviousness
Ichabod
bitter
apologize
F
regretter
sayang
seem like a good idea at the time
eat one's words
pang of conscience
regretfulness
pity
ochanee
repine
lamentably
aiyo
regretting
penance
alack and alas
penitence
repentance
stupor
shock