regret
US /rɪˈɡrɛt/
・UK /rɪ'ɡret/
B1
noun
- Feeling of being sorry, as for what you didn't do
verb
- To feel sorrow or guilt, as for what you didn't do
Examples
I immediately regretted not asking for his name and address.
I never learned to play an instrument and that's a matter of some regret.