What is a dry sense of humor?

A dry sense of humor is the tendency to find and appreciate something humorous in a situation that doesn't appear to have innate humor. A comedian with a dry sense of humor delivers amusing material in a deadpan manner.

Steven Wright is a perfect example of a stand-up comedian with a dry sense of humor. He does not try to entertain with clownish movements and dramatic voice; his on-stage delivery is completely monotone and emotionless. The staid, dry nature of his presentation stands in stark and comical contrast with the ridiculousness of his material, and creates a complete comedy package.