regret

American Heritage® Dictionary of the English Language, Fourth Edition

1. v. To feel sorry, disappointed, or distressed about.
2. v. To remember with a feeling of loss or sorrow; mourn.
3. v. To feel regret.
4. n. A sense of loss and longing for someone or something gone.
5. n. A feeling of disappointment or distress about something that one wishes could be different.
6. n. A courteous expression of regret, especially at having to decline an invitation.

Century Dictionary and Cyclopedia

1. To look back at with sorrow; feel grief or sorrowful longing for on looking back.
2. To grieve at; be mentally distressed on account of: as, to regret one's rashness; to regret a choice made.
3. Synonyms To rue, lament. See repentance.
4. n. Grief or trouble caused by the want or loss of something formerly possessed; a painful sense of loss; desire for what is gone; sorrowful longing.
5. n. Pain or distress of mind, as at something done or left undone; the earnest wish that something had not been done or did not exist; bitterness of reflection.
6. n. Dislike; aversion.
7. n. An expression of regret: commonly in the plural.
8. n. A written communication expressing sorrow for inability to accept an invitation.
9. n. Synonyms Concern, Sorrow, lamentation.
10. n. Penitence, Compunction, etc. See repentance.

Wiktionary

1. v. To feel sorry about (a thing that has happened), afterthink: to wish that a thing had not happened, that something else had happened instead.
2. v. more generally To feel sorry about (any thing).
3. n. The instance of such an emotion.

GNU Webster's 1913

1. n. Pain of mind on account of something done or experienced in the past, with a wish that it had been different; a looking back with dissatisfaction or with longing; grief; sorrow; especially, a mourning on account of the loss of some joy, advantage, or satisfaction.
2. n. obsolete Dislike; aversion.
3. v. To experience regret on account of; to lose or miss with a sense of regret; to feel sorrow or dissatisfaction on account of (the happening or the loss of something)

WordNet 3.0

1. v. feel sad about the loss or absence of
2. v. express with regret
3. v. feel remorse for; feel sorry for; be contrite about
4. v. decline formally or politely
5. n. sadness associated with some wrong done or some disappointment