Sanctimonious means acting like you're morally superior to others in an annoying, self-righteous way. A sanctimonious person doesn't just do the right thing; they make sure everyone knows they're doing it and often judge others who don't measure up to their standards.

Imagine a classmate who brings a healthy lunch and announces loudly, “I would never eat junk food like some people,” while staring pointedly at others. That's sanctimonious behavior. Or picture someone who volunteers once and then constantly reminds everyone about their good deed while criticizing those who haven't volunteered.

The word has a religious origin (from the Latin word for “holy”), and you'll sometimes hear about sanctimonious preachers who lecture others about sin while secretly misbehaving. But the word applies to anyone who acts holier-than-thou about anything: healthy eating, studying hard, following rules, or protecting the environment.

What makes someone sanctimonious isn't their good behavior, it's their attitude about it. Someone can be genuinely good and humble, or they can be sanctimonious and insufferable. The difference is whether they use their choices as a weapon to make others feel small. When you hear this word, it's almost always a criticism: nobody wants to be called sanctimonious, and nobody enjoys being around sanctimonious people.