ultimatum,unleash,unnerve,unrest,upbeat

ultimatum 最後通牒

We issued an ultimatum and gave them three days to response.

unleash 解除...的束縛 發動

Region Three is expected to unleash its new operating system in March.

unnerve 使喪失信心 使氣餒

He has the ability to unnerve even the most confident applicant.

unrest 動盪

Shutting down the giant corporations will bring large-scale unemployment and possibly civil unrest.

upbeat 令人鼓舞的 樂觀的

Doctors were upbeat today as they submitted their vaccine for FDA approval.