To deplore means to strongly disapprove of something or to feel and express deep regret or sadness about it. When you deplore something, you find it truly wrong, unfortunate, or deeply upsetting, going beyond mild annoyance to serious moral concern.

A teacher might deplore the way some students treat the new kid, meaning she finds that behavior seriously wrong and disappointing. A community might deplore the vandalism of a local park, expressing both sadness that it happened and strong disapproval of whoever did it. Someone might deplore cruelty to animals, believing it causes real harm and suffering.

The word carries weight and seriousness. You wouldn't say you deplore burnt toast, but you might deplore cruelty or dishonesty. It suggests both moral disapproval and genuine sadness or concern about something you believe shouldn't happen. When someone says a situation is deplorable, they mean it's so bad that it deserves strong condemnation.

When you deplore something, you're saying it troubles you deeply, not just that you dislike it.