To commend someone means to praise them formally or officially for something they've done well. When a teacher commends you for your effort on a project, she's giving you recognition that acknowledges your hard work in a serious, meaningful way: an official statement of approval rather than a casual compliment.

The word carries a sense of authority and respect. A principal might commend a student for helping a new classmate feel welcome. A general might commend a soldier for bravery. A boss might commend an employee for exceptional work. The praise comes from someone in a position to judge quality or character, and it often happens publicly so others can recognize the achievement too.

You might also commend someone to another person, meaning you recommend them highly: “I commend this book to you” means “I think you'll find this book valuable, and I'm vouching for its quality.”

The related word commendable describes something worthy of praise: a commendable effort means one that deserves recognition, even if the final result wasn't perfect.