To Regret

1. To 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.
2. (more generally) To feel sorry about (any thing).
3. (archaic, transitive) To miss; to feel the loss or absence of; to mourn.

Usage notes

• "Regret" is a catenative verb that takes the gerund (the -ing form), except in set phrases with tell, say, and inform, where the to infinitive is used. See Appendix:English catenative verbs