Wiktionary
unamusing
a. Not amusing.
WordNet
unamusing
adj. not amusing; "his jokes were labored and unamusing"
Usage examples of "unamusing".
This was caricaturing, making a parody of her art and what she did, an unamusing joke against herself.
But sometimes she would talk, and treat her hearers to her recollections, and recount anecdotes with a sort of grim cleverness, not wholly unamusing.