Crass/kræs/ Definition 1 of 2Pro Tip 1/3Not Subtle Crass doesn't just mean rude; it's rudeness from not noticing subtleties. Laughing at someone's mistake could be seen as crass. Pro Tip 2/3Very Blunt Using crass is strong criticism; it suggests a person is extremely blunt. Her crass way of speaking hurt her friends. Pro Tip 3/3Avoid in Formality Crass is informal and negative, avoid it in formal or polite conversation. It's crass to discuss money at a formal dinner.