Definition of "Regret" :

noun: sadness associated with some wrong done or some disappointment

"He wrote a note expressing his regret."

verb: express with regret

"I regret to say that you did not gain admission to Harvard."

verb: decline formally or politely

"I regret I can't come to the party."

verb: feel remorse for; feel sorry for; be contrite about

verb: feel sad about the loss or absence of