1. in a way that is very rude, insensitive, or lacking in refinement or good taste
2. in a way that is obviously or grossly wrong, stupid, or lacking in subtlety

Examples

• He crassly interrupted her during the presentation without apologizing.
• The comedian's jokes were crassly offensive to many audience members.
• She crassly asked about his salary at their first meeting.
• The advertisement crassly exploited people's insecurities to sell the product.
• He crassly dismissed her concerns as unimportant.
• The politician crassly pandered to the crowd with empty promises.