1.nounEmotional pain 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.
2.nounDislike; aversion.
3.verbTo feel sorry about (a thing that has or has not happened), afterthink: to wish that a thing had not happened, that something else had happened instead.
"He regretted his words."
4.verb(more generally) To feel sorry about (any thing).
"I regret that I have to do this, but I don't have a choice."