1. lacking humor; not funny or amusing
2. unable or unwilling to appreciate or express humor; lacking a sense of humor

Examples

• The presentation was humourless and put the entire audience to sleep.
• He gave a humourless response to her joke, which made the situation awkward.
• The film's humourless tone made it difficult to enjoy despite its interesting plot.
• She has a humourless personality and rarely laughs at anything.
• The humourless bureaucrat refused to bend any rules, no matter the circumstances.
• His humourless delivery of the punchline ruined the entire joke.