（因为不能赴会等）（向某人）表示歉意，致歉辞谢
to send a polite message that you cannot go to a party, etc.
We did have an invitation, but we had to send Graham our regrets. 我们确实收到了请柬，但是我们脱不开身，不得不向格雷厄姆致歉辞谢。
Daniel was unwell at the time so we sent our regrets.
I think we might have to send our regrets.
The couple were indisposed so sent their regrets.
The President, it was reported, had sent the Prime Minister his regrets.
He thanks you for your kind invitation but sends his regrets.
See also: regret noun