regret regret /rɪˈgrɛt/

noun

1. () Sadness associated with some wrong done or some disappointment  ( rue [Archaic] , ruefulness , sorrow , regret )
   sadness associated with some wrong done or some disappointment
    He drank to drown his sorrows
   he drank to drown his sorrows
    He wrote a note expressing his regret
   he wrote a note expressing his regret
    To his rue, the error cost him the game
   to his rue, the error cost him the game
   
   

verb

1. () Feel remorse for; feel sorry for; be contrite about  ( repent , rue , regret )
   feel remorse for; feel sorry for; be contrite about
     I regret not taking the chance to study abroad when I had the opportunity.
   I regret not taking the chance to study abroad when I had the opportunity.
   
2. () Feel sad about the loss or absence of  ( regret )
   feel sad about the loss or absence of
   
3. () Express with regret  ( regret )
   express with regret
    I regret to say that you did not gain admission to Harvard
   I regret to say that you did not gain admission to Harvard
   
4. () Decline formally or politely  ( regret )
   decline formally or politely
    I regret I can't come to the party
   I regret I can't come to the party