quake / kwāk/ • v. [intr.] (esp. of the earth) shake or tremble: the rumbling vibrations set the whole valley quaking. ∎ (of a person) shake or shudder with fear: those words should have them quaking in their boots. • n. inf. an earthquake. ∎ [usu. in sing.] an act of shaking or quaking. DERIVATIVES: quak·y adj. (quak·i·er , quak·i·est ) .