anticlimactic

the opposite of building to a climax. instead, making potentially rising ideas and energy steady, or falling.

relating to a person's tone of voice; sounding dull, less enthusiastic, or normal tone in cases of excitement.

Sarcasm would be an example of being anticlimactic.

"Oh WOW! that sounds soooo...exciting..."
"That was sure anti-climactic"

62👍 33👎