目を覚ませよ！

！

Wake up!

Literal

Eyes [obj-を] awaken [imperative-よ]!

目を覚ませ is the rough imperative of 目を覚ます ('wake up'). 覚ませ is the imperative form of the godan verb 覚ます. よ adds urgency. Forceful and abrupt — used in emergencies or strong frustration.