Which word describes the action of trembling, shaking or quivering?

The correct term that describes the action of trembling, shaking, or quivering is "palpitate." This word is often used in medical contexts to refer to a rapid or irregular heartbeat, which creates a sensation of shaking or quivering in the body. It captures the essence of involuntary movement, making it particularly relevant to the question.

The other terms listed have distinct meanings that do not relate to trembling or shaking. For instance, "patois" refers to a dialect or regional form of language that is often considered nonstandard. "Ostentation" describes a display of wealth or knowledge intended to attract attention or admiration, while "penurious" means extremely poor or poverty-stricken, relating to a lack of resources rather than physical movement. Thus, "palpitate" is the precise term that conveys the action described in the question.