a feeling of sadness about something sad or wrong or about a mistake that you have made, and a wish that it could have been different and betterI left school at 16, but I've had a great life and I have no regrets.
The manager expressed deep regret at/for the number of staff reductions.
We think, much to our regret (= and we are very sorry about this), that we will not be able to visit you next year.
send (sb) your regrets to send a polite message that you cannot go to a party, etcWe did have an invitation, but we had to send Graham our regrets.