Jeu D'esprit is a French term that refers to a witty, playful, and clever thought or expression. Its antonyms could be dull, banal, tedious, boring, and uninteresting. Dull refers to something lacking in excitement, interest, or vitality. Banal denotes something that is common or unoriginal. Tedious refers to anything that is boring, monotonous, or lengthy. Boring is self-explanatory - it means something or someone that doesn't induce any interest or excitement. Uninteresting refers to something that is devoid of any intriguing or captivating aspects. Thus, all of these terms are antonyms to the intriguing and amusing Jeu D'esprit.